diff --git a/includes/debug/DeprecationHelper.php b/includes/debug/DeprecationHelper.php
index 2ea5c47d9b6..8a7d2396e9e 100644
--- a/includes/debug/DeprecationHelper.php
+++ b/includes/debug/DeprecationHelper.php
@@ -22,7 +22,8 @@
 
 /**
  * Use this trait in classes which have properties for which public access
- * is deprecated. Set the list of properties in $deprecatedPublicProperties
+ * is deprecated or implementation has been move to another class.
+ * Set the list of properties in $deprecatedPublicProperties
  * and make the properties non-public. The trait will preserve public access
  * but issue deprecation warnings when it is needed.
  *
@@ -32,11 +33,25 @@
  *         protected $bar;
  *         public function __construct() {
  *             $this->deprecatePublicProperty( 'bar', '1.21', __CLASS__ );
+ *             $this->deprecatePublicPropertyFallback(
+ *                 'movedValue',
+ *                 '1.35',
+ *                 function () {
+ *                     return MediawikiServices()::getInstance()
+ *                         ->getNewImplementationService()->getValue();
+ *                 },
+ *                 function ( $value ) {
+ *                     MediawikiServices()::getInstance()
+ *                         ->getNewImplementationService()->setValue( $value );
+ *                 }
+ *             );
  *         }
  *     }
  *
  *     $foo = new Foo;
  *     $foo->bar; // works but logs a warning
+ *     $foo->movedValue = 10; // works but logs a warning
+ *     $movedValue = $foo->movedValue; // also works
  *
  * Cannot be used with classes that have their own __get/__set methods.
  *
@@ -45,8 +60,9 @@
 trait DeprecationHelper {
 
 	/**
-	 * List of deprecated properties, in <property name> => [<version>, <class>, <component>] format
-	 * where <version> is the MediaWiki version where the property got deprecated, <class> is the
+	 * List of deprecated properties, in <property name> => [<version>, <class>,
+	 * <component>, <getter>, <setter> ] format where <version> is the MediaWiki version
+	 * where the property got deprecated, <class> is the
 	 * the name of the class defining the property, <component> is the MediaWiki component
 	 * (extension, skin etc.) for use in the deprecation warning) or null if it is MediaWiki.
 	 * E.g. [ 'mNewRev' => [ '1.32', 'DifferenceEngine', null ]
@@ -57,6 +73,9 @@ trait DeprecationHelper {
 	/**
 	 * Mark a property as deprecated. Only use this for properties that used to be public and only
 	 *   call it in the constructor.
+	 *
+	 * @note  Providing callbacks makes it not serializable
+	 *
 	 * @param string $property The name of the property.
 	 * @param string $version MediaWiki version where the property became deprecated.
 	 * @param string|null $class The class which has the deprecated property. This can usually be
@@ -66,16 +85,60 @@ trait DeprecationHelper {
 	 * @see wfDeprecated()
 	 */
 	protected function deprecatePublicProperty(
-		$property, $version, $class = null, $component = null
+		$property,
+		$version,
+		$class = null,
+		$component = null
 	) {
-		$this->deprecatedPublicProperties[$property] = [ $version, $class ?: __CLASS__, $component ];
+		$this->deprecatedPublicProperties[$property] = [
+			$version,
+			$class ?: __CLASS__,
+			$component,
+			null, null
+		];
+	}
+
+	/**
+	 * Mark a removed public property as deprecated and provide fallback getter and setter callables.
+	 * Only use this for properties that used to be public and only
+	 * call it in the constructor.
+	 *
+	 * @param string $property The name of the property.
+	 * @param string $version MediaWiki version where the property became deprecated.
+	 * @param callable $getter an user provided getter that implements a `get` logic for the property
+	 * @param callable|null $setter an user provided getter that implements a `set` logic for the property
+	 * @param string|null $class The class which has the deprecated property.
+	 * @param string|null $component
+	 *
+	 * @since 1.36
+	 * @see wfDeprecated()
+	 */
+	protected function deprecatePublicPropertyFallback(
+		string $property,
+		string $version,
+		callable $getter,
+		?callable $setter = null,
+		$class = null,
+		$component = null
+	) {
+		$this->deprecatedPublicProperties[$property] = [
+			$version,
+			$class ?: __CLASS__,
+			null,
+			$getter,
+			$setter,
+			$component
+		];
 	}
 
 	public function __get( $name ) {
 		if ( isset( $this->deprecatedPublicProperties[$name] ) ) {
-			list( $version, $class, $component ) = $this->deprecatedPublicProperties[$name];
+			list( $version, $class, $component, $getter ) = $this->deprecatedPublicProperties[$name];
 			$qualifiedName = $class . '::$' . $name;
 			wfDeprecated( $qualifiedName, $version, $component, 3 );
+			if ( $getter ) {
+				return $getter();
+			}
 			return $this->$name;
 		}
 
@@ -93,10 +156,16 @@ trait DeprecationHelper {
 
 	public function __set( $name, $value ) {
 		if ( isset( $this->deprecatedPublicProperties[$name] ) ) {
-			list( $version, $class, $component ) = $this->deprecatedPublicProperties[$name];
+			list( $version, $class, $component, , $setter ) = $this->deprecatedPublicProperties[$name];
 			$qualifiedName = $class . '::$' . $name;
 			wfDeprecated( $qualifiedName, $version, $component, 3 );
-			$this->$name = $value;
+			if ( $setter ) {
+				$setter( $value );
+			} elseif ( property_exists( $this, $name ) ) {
+				$this->$name = $value;
+			} else {
+				trigger_error( "Cannot access non-public property $qualifiedName", E_USER_ERROR );
+			}
 			return;
 		}
 
diff --git a/includes/language/ConverterRule.php b/includes/language/ConverterRule.php
index 24f30383660..996dd2747c1 100644
--- a/includes/language/ConverterRule.php
+++ b/includes/language/ConverterRule.php
@@ -91,7 +91,7 @@ class ConverterRule {
 
 		$sepPos = strpos( $text, '|' );
 		if ( $sepPos !== false ) {
-			$validFlags = $this->mConverter->mFlags;
+			$validFlags = $this->mConverter->getFlags();
 			$f = StringUtils::explode( ';', substr( $text, 0, $sepPos ) );
 			foreach ( $f as $ff ) {
 				$ff = trim( $ff );
@@ -189,7 +189,7 @@ class ConverterRule {
 				}
 			}
 			// syntax error, pass
-			if ( !isset( $this->mConverter->mVariantNames[$vv] ) ) {
+			if ( !isset( $this->mConverter->getVariantNames()[$vv] ) ) {
 				$bidtable = [];
 				$unidtable = [];
 				break;
@@ -203,15 +203,15 @@ class ConverterRule {
 	 * @return string
 	 */
 	private function getRulesDesc() {
-		$codesep = $this->mConverter->mDescCodeSep;
-		$varsep = $this->mConverter->mDescVarSep;
+		$codesep = $this->mConverter->getDescCodeSeparator();
+		$varsep = $this->mConverter->getDescVarSeparator();
 		$text = '';
 		foreach ( $this->mBidtable as $k => $v ) {
-			$text .= $this->mConverter->mVariantNames[$k] . "$codesep$v$varsep";
+			$text .= $this->mConverter->getVariantNames()[$k] . "$codesep$v$varsep";
 		}
 		foreach ( $this->mUnidtable as $k => $a ) {
 			foreach ( $a as $from => $to ) {
-				$text .= $from . '⇒' . $this->mConverter->mVariantNames[$k] .
+				$text .= $from . '⇒' . $this->mConverter->getVariantNames()[$k] .
 					"$codesep$to$varsep";
 			}
 		}
@@ -245,7 +245,7 @@ class ConverterRule {
 			$disp = array_values( $unidtable[$variant] )[0];
 		}
 		// or display first text under disable manual convert
-		if ( $disp === false && $this->mConverter->mManualLevel[$variant] === 'disable' ) {
+		if ( $disp === false && $this->mConverter->getManualLevel()[$variant] === 'disable' ) {
 			if ( count( $bidtable ) > 0 ) {
 				$disp = array_values( $bidtable )[0];
 			} else {
@@ -258,7 +258,7 @@ class ConverterRule {
 
 	/**
 	 * Similar to getRuleConvertedStr(), but this prefers to use original
-	 * page title if $variant === $this->mConverter->mMainLanguageCode
+	 * page title if $variant === $this->mConverter->getMainCode()
 	 * and may return false in this case (so this title conversion rule
 	 * will be ignored and the original title is shown).
 	 *
@@ -267,7 +267,7 @@ class ConverterRule {
 	 * @return string|bool The converted title or false if just page name
 	 */
 	private function getRuleConvertedTitle( $variant ) {
-		if ( $variant === $this->mConverter->mMainLanguageCode ) {
+		if ( $variant === $this->mConverter->getMainCode() ) {
 			// If a string targeting exactly this variant is set,
 			// use it. Otherwise, just return false, so the real
 			// page name can be shown (and because variant === main,
@@ -298,10 +298,10 @@ class ConverterRule {
 
 		$bidtable = $this->mBidtable;
 		$unidtable = $this->mUnidtable;
-		$manLevel = $this->mConverter->mManualLevel;
+		$manLevel = $this->mConverter->getManualLevel();
 
 		$vmarked = [];
-		foreach ( $this->mConverter->mVariants as $v ) {
+		foreach ( $this->mConverter->getVariants() as $v ) {
 			/* for bidirectional array
 				fill in the missing variants, if any,
 				with fallbacks */
@@ -395,7 +395,7 @@ class ConverterRule {
 			if ( isset( $flags['+'] ) || isset( $flags['-'] ) ) {
 				// fill all variants if text in -{A/H/-|text}- is non-empty but without rules
 				if ( $rules !== '' ) {
-					foreach ( $this->mConverter->mVariants as $v ) {
+					foreach ( $this->mConverter->getVariants() as $v ) {
 						$this->mBidtable[$v] = $rules;
 					}
 				}
@@ -414,7 +414,7 @@ class ConverterRule {
 				case 'N':
 					// process N flag: output current variant name
 					$ruleVar = trim( $rules );
-					$this->mRuleDisplay = $this->mConverter->mVariantNames[$ruleVar] ?? '';
+					$this->mRuleDisplay = $this->mConverter->getVariantNames()[$ruleVar] ?? '';
 					break;
 				case 'D':
 					// process D flag: output rules description
diff --git a/includes/language/ILanguageConverter.php b/includes/language/ILanguageConverter.php
index fe3c400169b..27da7c3e26f 100644
--- a/includes/language/ILanguageConverter.php
+++ b/includes/language/ILanguageConverter.php
@@ -29,7 +29,6 @@ interface ILanguageConverter {
 
 	/**
 	 * Get all valid variants.
-	 * Call this instead of using $this->mVariants directly.
 	 * @return string[] Contains all valid variants
 	 */
 	public function getVariants();
diff --git a/includes/language/LanguageConverter.php b/includes/language/LanguageConverter.php
index d37e80d03a2..10a72d5e569 100644
--- a/includes/language/LanguageConverter.php
+++ b/includes/language/LanguageConverter.php
@@ -55,14 +55,6 @@ abstract class LanguageConverter implements ILanguageConverter {
 		'zh',
 	];
 
-	public $mMainLanguageCode;
-
-	/**
-	 * @var string[]
-	 */
-	public $mVariants;
-	private $mVariantFallbacks;
-	public $mVariantNames;
 	private $mTablesLoaded = false;
 
 	/**
@@ -70,16 +62,11 @@ abstract class LanguageConverter implements ILanguageConverter {
 	 */
 	protected $mTables;
 
-	/** @var string[] One of 'bidirectional' 'unidirectional' 'disable' for each variant */
-	public $mManualLevel;
-
 	/**
 	 * @var Language
 	 */
 	private $mLangObj;
-	public $mFlags;
-	public $mDescCodeSep = ':';
-	public $mDescVarSep = ';';
+
 	private $mUcfirst = false;
 	private $mConvRuleTitle = false;
 	private $mURLVariant;
@@ -92,23 +79,8 @@ abstract class LanguageConverter implements ILanguageConverter {
 
 	/**
 	 * @param Language $langobj
-	 * @param string $maincode The main language code of this language
-	 * @param string[] $variants The supported variants of this language
-	 * @param array $variantfallbacks The fallback language of each variant
-	 * @param array $flags Defining the custom strings that maps to the flags
-	 * @param array $manualLevel Limit for supported variants
 	 */
-	public function __construct(
-		$langobj,
-		$maincode,
-		$variants = [],
-		$variantfallbacks = [],
-		$flags = [],
-		$manualLevel = []
-	) {
-		global $wgDisabledVariants;
-
-		$this->deprecatePublicProperty( 'mURLVariant', '1.35', __CLASS__ );
+	public function __construct( $langobj ) {
 		$this->deprecatePublicProperty( 'mUcfirst', '1.35', __CLASS__ );
 		$this->deprecatePublicProperty( 'mConvRuleTitle', '1.35', __CLASS__ );
 		$this->deprecatePublicProperty( 'mUserVariant', '1.35', __CLASS__ );
@@ -121,12 +93,67 @@ abstract class LanguageConverter implements ILanguageConverter {
 		$this->deprecatePublicProperty( 'mTables', '1.35', __CLASS__ );
 
 		$this->mLangObj = $langobj;
-		$this->mMainLanguageCode = $maincode;
-		$this->mVariants = array_diff( $variants, $wgDisabledVariants );
-		$this->mVariantFallbacks = $variantfallbacks;
-		$this->mVariantNames = MediaWikiServices::getInstance()
-			->getLanguageNameUtils()
-			->getLanguageNames();
+
+		$this->deprecatePublicPropertyFallback( 'mVariants', '1.36', function () {
+			return $this->getVariants();
+		} );
+
+		$this->deprecatePublicPropertyFallback( 'mMainLanguageCode', '1.36', function () {
+			return $this->getMainCode();
+		} );
+
+		$this->deprecatePublicPropertyFallback( 'mVariantFallbacks', '1.36', function () {
+			return $this->getVariantsFallbacks();
+		} );
+
+		$this->deprecatePublicPropertyFallback( 'mFlags', '1.36', function () {
+			return $this->getFlags();
+		} );
+
+		$this->deprecatePublicPropertyFallback( 'mVariantNames', '1.36', function () {
+			return $this->getVariantNames();
+		} );
+
+		$this->deprecatePublicPropertyFallback( 'mDescCodeSep', '1.36', function () {
+			return $this->getDescCodeSeparator();
+		} );
+
+		$this->deprecatePublicPropertyFallback( 'mDescVarSep', '1.36', function () {
+			return $this->getDescVarSeparator();
+		} );
+	}
+
+	/**
+	 * Get main language code.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	abstract public function getMainCode(): string;
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	abstract protected function getLanguageVariants(): array;
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	abstract public function getVariantsFallbacks(): array;
+
+	/**
+	 * Get strings that maps to the flags.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	final public function getFlags(): array {
 		$defaultflags = [
 			// 'S' show converted text
 			// '+' add rules for alltext
@@ -140,25 +167,94 @@ abstract class LanguageConverter implements ILanguageConverter {
 			'H' => 'H',   // add rule for convert code (but no display in placed code)
 			'N' => 'N',   // current variant name
 		];
-		$this->mFlags = array_merge( $defaultflags, $flags );
-		foreach ( $this->mVariants as $v ) {
-			if ( array_key_exists( $v, $manualLevel ) ) {
-				$this->mManualLevel[$v] = $manualLevel[$v];
-			} else {
-				$this->mManualLevel[$v] = 'bidirectional';
-			}
-			$this->mFlags[$v] = $v;
+		$flags = array_merge( $defaultflags, $this->getAdditionalFlags() );
+		foreach ( $this->getVariants() as $v ) {
+			$flags[$v] = $v;
 		}
+		return $flags;
 	}
 
 	/**
-	 * Get all valid variants.
-	 * Call this instead of using $this->mVariants directly.
+	 * Provides additinal flags for converter. By default it return empty array and
+	 * typicslly should be overridden by implementation of converter..
+	 *
+	 * @return array
+	 */
+	protected function getAdditionalFlags(): array {
+		return [];
+	}
+
+	/**
+	 * Get manual level limit for supported variants.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	final public function getManualLevel() {
+		$manualLevel  = $this->getAdditionalManualLevel();
+		$result = [];
+		foreach ( $this->getVariants() as $v ) {
+			if ( array_key_exists( $v, $manualLevel ) ) {
+				$result[$v] = $manualLevel[$v];
+			} else {
+				$result[$v] = 'bidirectional';
+			}
+		}
+		return $result;
+	}
+
+	/**
+	 * Provides additinal flags for converter. By default it return empty array and
+	 * typicslly should be overridden by implementation of converter.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	protected function getAdditionalManualLevel(): array {
+		return [];
+	}
+
+	/**
+	 * Get desc code separator. By default returns ":", can be overridden by
+	 * implementation of converter.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getDescCodeSeparator(): string {
+		return ':';
+	}
+
+	/**
+	 * Get desc var separator. By default returns ";", can be overridden by
+	 * implementation of converter.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getDescVarSeparator(): string {
+		return ';';
+	}
+
+	/**
+	 * Get variant names.
+	 *
+	 * @return array
+	 */
+	public function getVariantNames(): array {
+		return MediaWikiServices::getInstance()
+			->getLanguageNameUtils()
+			->getLanguageNames();
+	}
+
+	/**
+	 * Get all valid variants for current Coverter. It uses abstract
 	 *
 	 * @return string[] Contains all valid variants
 	 */
-	public function getVariants() {
-		return $this->mVariants;
+	final public function getVariants() {
+		global $wgDisabledVariants;
+		return array_diff( $this->getLanguageVariants(), $wgDisabledVariants );
 	}
 
 	/**
@@ -173,7 +269,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 	 *   main code if there is no fallback
 	 */
 	public function getVariantFallbacks( $variant ) {
-		return $this->mVariantFallbacks[$variant] ?? $this->mMainLanguageCode;
+		return $this->getVariantsFallbacks()[$variant] ?? $this->getMainCode();
 	}
 
 	/**
@@ -217,7 +313,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 		if ( $req ) {
 			return $req;
 		}
-		return $this->mMainLanguageCode;
+		return $this->getMainCode();
 	}
 
 	/**
@@ -240,7 +336,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 		if ( $req ) {
 			return $req;
 		}
-		return $this->mMainLanguageCode;
+		return $this->getMainCode();
 	}
 
 	/**
@@ -259,14 +355,14 @@ abstract class LanguageConverter implements ILanguageConverter {
 		// Our internal variants are always lower-case; the variant we
 		// are validating may have mixed case.
 		$variant = LanguageCode::replaceDeprecatedCodes( strtolower( $variant ) );
-		if ( in_array( $variant, $this->mVariants ) ) {
+		if ( in_array( $variant, $this->getVariants() ) ) {
 			return $variant;
 		}
 		// Browsers are supposed to use BCP 47 standard in the
 		// Accept-Language header, but not all of our internal
 		// mediawiki variant codes are BCP 47.  Map BCP 47 code
 		// to our internal code.
-		foreach ( $this->mVariants as $v ) {
+		foreach ( $this->getVariants() as $v ) {
 			// Case-insensitive match (BCP 47 is mixed case)
 			if ( strtolower( LanguageCode::bcp47( $v ) ) === $variant ) {
 				return $v;
@@ -314,12 +410,12 @@ abstract class LanguageConverter implements ILanguageConverter {
 		if ( $user->isRegistered() ) {
 			// Get language variant preference from logged in users
 			if (
-				$this->mMainLanguageCode ==
+				$this->getMainCode() ==
 				MediaWikiServices::getInstance()->getContentLanguage()->getCode()
 			) {
 				$ret = $user->getOption( 'variant' );
 			} else {
-				$ret = $user->getOption( 'variant-' . $this->mMainLanguageCode );
+				$ret = $user->getOption( 'variant-' . $this->getMainCode() );
 			}
 		} else {
 			// figure out user lang without constructing wgLang to avoid
@@ -361,7 +457,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 			// We record these fallback variants, and process
 			// them later.
 			$fallbacks = $this->getVariantFallbacks( $language );
-			if ( is_string( $fallbacks ) && $fallbacks !== $this->mMainLanguageCode ) {
+			if ( is_string( $fallbacks ) && $fallbacks !== $this->getMainCode() ) {
 				$fallbackLanguages[] = $fallbacks;
 			} elseif ( is_array( $fallbacks ) ) {
 				$fallbackLanguages =
@@ -573,7 +669,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 		$this->loadTables();
 
 		$ret = [];
-		foreach ( $this->mVariants as $variant ) {
+		foreach ( $this->getVariants() as $variant ) {
 			$ret[$variant] = $this->translate( $text, $variant );
 		}
 
@@ -987,7 +1083,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 		// Do not use null as starting value, as that would confuse phan a lot.
 		$this->mTables = [];
 		$cache = ObjectCache::getInstance( $wgLanguageConverterCacheType );
-		$cacheKey = $cache->makeKey( 'conversiontables', $this->mMainLanguageCode );
+		$cacheKey = $cache->makeKey( 'conversiontables', $this->getMainCode() );
 		if ( $fromCache ) {
 			$this->mTables = $cache->get( $cacheKey );
 		}
@@ -996,7 +1092,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 			// We will first load the default tables
 			// then update them using things in MediaWiki:Conversiontable/*
 			$this->loadDefaultTables();
-			foreach ( $this->mVariants as $var ) {
+			foreach ( $this->getVariants() as $var ) {
 				$cached = $this->parseCachedTable( $var );
 				// @phan-suppress-next-next-line PhanTypeArraySuspiciousNullable
 				// FIXME: $this->mTables could theoretically be null here
@@ -1228,7 +1324,7 @@ abstract class LanguageConverter implements ILanguageConverter {
 			//    [2] => ''
 			//  ]
 			$expandedVariants = [];
-			foreach ( $this->mVariants as $variant ) {
+			foreach ( $this->getVariants() as $variant ) {
 				$expandedVariants[ $variant ] = 1;
 				// Accept standard BCP 47 names for variants as well.
 				$expandedVariants[ LanguageCode::bcp47( $variant ) ] = 1;
diff --git a/includes/language/LanguageConverterIcu.php b/includes/language/LanguageConverterIcu.php
index dcad508171c..9ffa98f73dd 100644
--- a/includes/language/LanguageConverterIcu.php
+++ b/includes/language/LanguageConverterIcu.php
@@ -36,7 +36,7 @@ abstract class LanguageConverterIcu extends LanguageConverterSpecific {
 	 */
 	protected function loadDefaultTables() {
 		$this->mTables = [];
-		foreach ( $this->mVariants as $variant ) {
+		foreach ( $this->getVariants() as $variant ) {
 			$this->mTables[$variant] = new ReplacementArray();
 		}
 	}
diff --git a/includes/language/LanguageConverterSpecific.php b/includes/language/LanguageConverterSpecific.php
index 13efb336d61..5f98dc7da0d 100644
--- a/includes/language/LanguageConverterSpecific.php
+++ b/includes/language/LanguageConverterSpecific.php
@@ -45,7 +45,7 @@ abstract class LanguageConverterSpecific extends LanguageConverter {
 
 		$oldlink = $link;
 		parent::findVariantLink( $link, $nt, $ignoreOtherCond );
-		if ( $this->getPreferredVariant() == $this->mMainLanguageCode ) {
+		if ( $this->getPreferredVariant() == $this->getMainCode() ) {
 			$link = $oldlink;
 		}
 	}
diff --git a/includes/language/TrivialLanguageConverter.php b/includes/language/TrivialLanguageConverter.php
index 5c1c75dab9e..e6bf03dfc11 100644
--- a/includes/language/TrivialLanguageConverter.php
+++ b/includes/language/TrivialLanguageConverter.php
@@ -45,6 +45,14 @@ class TrivialLanguageConverter implements ILanguageConverter {
 	 */
 	private $titleFormatter;
 
+	/**
+	 * Creates a converter for languages that don't have variants. This method is internal
+	 * and should be called for LanguageConverterFactory only
+	 *
+	 * @param Language $langobj
+	 *
+	 * @internal
+	 */
 	public function __construct( $langobj ) {
 		$this->language = $langobj;
 		$this->titleFormatter = MediaWikiServices::getInstance()->getTitleFormatter();
diff --git a/includes/language/converters/BanConverter.php b/includes/language/converters/BanConverter.php
index b728d35c442..80d06bd1051 100644
--- a/includes/language/converters/BanConverter.php
+++ b/includes/language/converters/BanConverter.php
@@ -28,19 +28,41 @@
 class BanConverter extends LanguageConverterIcu {
 
 	/**
-	 * @param Language $langobj
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'ban', 'ban-bali', 'ban-x-dharma', 'ban-x-palmleaf', 'ban-x-pku' ];
-		$variantfallbacks = [
+	public function getMainCode(): string {
+		return 'ban';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'ban', 'ban-bali', 'ban-x-dharma', 'ban-x-palmleaf', 'ban-x-pku' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'ban-bali' => 'ban',
 			'ban-x-dharma' => 'ban',
 			'ban-x-palmleaf' => 'ban',
 			'ban-x-pku' => 'ban',
 		];
+	}
 
-		parent::__construct( $langobj, 'ban', $variants, $variantfallbacks, [] );
-
+	public function getVariantNames(): array {
 		$names = [
 			'ban' => 'Basa Bali',
 			'ban-bali' => 'ᬩᬲᬩᬮᬶ',
@@ -48,7 +70,7 @@ class BanConverter extends LanguageConverterIcu {
 			'ban-x-palmleaf' => 'Basa Bali (alih aksara Palmleaf.org)',
 			'ban-x-pku' => 'Basa Bali (alih aksara Puri Kauhan Ubud)',
 		];
-		$this->mVariantNames = array_merge( $this->mVariantNames, $names );
+		return array_merge( parent::getVariantNames(), $names );
 	}
 
 	protected function getIcuRules() {
diff --git a/includes/language/converters/CrhConverter.php b/includes/language/converters/CrhConverter.php
index 8134d5c442c..612e8d2c88a 100644
--- a/includes/language/converters/CrhConverter.php
+++ b/includes/language/converters/CrhConverter.php
@@ -75,18 +75,44 @@ class CrhConverter extends LanguageConverterSpecific {
 	public const L_F = 'eiöüEİÖÜ';
 
 	/**
-	 * @param Language $langobj
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'crh', 'crh-cyrl', 'crh-latn' ];
-		$variantfallbacks = [
+	public function getMainCode(): string {
+		return 'crh';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'crh', 'crh-cyrl', 'crh-latn' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'crh' => 'crh-latn',
 			'crh-cyrl' => 'crh-latn',
 			'crh-latn' => 'crh-cyrl',
 		];
+	}
 
-		parent::__construct( $langobj, 'crh',
-			$variants, $variantfallbacks, [] );
+	/**
+	 * @param Language $langobj
+	 */
+	public function __construct( $langobj ) {
+		parent::__construct( $langobj );
 
 		// No point delaying this since they're in code.
 		// Waiting until loadDefaultTables() means they never get loaded
@@ -270,5 +296,4 @@ class CrhConverter extends LanguageConverterSpecific {
 				return $text;
 		}
 	}
-
 }
diff --git a/includes/language/converters/EnConverter.php b/includes/language/converters/EnConverter.php
index c9270d75bde..7f7825c0ed9 100644
--- a/includes/language/converters/EnConverter.php
+++ b/includes/language/converters/EnConverter.php
@@ -25,13 +25,36 @@
  */
 class EnConverter extends LanguageConverter {
 
-	public function __construct( $langobj ) {
-		parent::__construct( $langobj, 'en', [ 'en', 'en-x-piglatin' ] );
+	/**
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getMainCode(): string {
+		return 'en';
 	}
 
 	/**
-	 * Dummy methods required by base class.
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
 	 */
+	public function getLanguageVariants(): array {
+		return [ 'en', 'en-x-piglatin' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [];
+	}
+
 	protected function loadDefaultTables() {
 		$this->mTables = [
 			'en' => new ReplacementArray(),
diff --git a/includes/language/converters/GanConverter.php b/includes/language/converters/GanConverter.php
index 4435b196dba..e195710ddee 100644
--- a/includes/language/converters/GanConverter.php
+++ b/includes/language/converters/GanConverter.php
@@ -24,36 +24,84 @@
  * @ingroup Language
  */
 class GanConverter extends LanguageConverter {
-	/**
-	 * @param Language $langobj
-	 */
-	public function __construct( $langobj ) {
-		$this->mDescCodeSep = '：';
-		$this->mDescVarSep = '；';
 
-		$variants = [ 'gan', 'gan-hans', 'gan-hant' ];
-		$variantfallbacks = [
+	/**
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getMainCode(): string {
+		return 'gan';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'gan', 'gan-hans', 'gan-hant' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'gan' => [ 'gan-hans', 'gan-hant' ],
 			'gan-hans' => [ 'gan' ],
 			'gan-hant' => [ 'gan' ],
 		];
-		$ml = [
-			'gan' => 'disable',
-		];
+	}
 
-		parent::__construct( $langobj, 'gan',
-			$variants,
-			$variantfallbacks,
-			[],
-			$ml
-		);
+	/**
+	 * Get manual level limit for supported variants.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	protected function getAdditionalManualLevel(): array {
+		return [ 'gan' => 'disable' ];
+	}
 
+	/**
+	 * Get desc. code separator.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getDescCodeSeparator(): string {
+		return ': ';
+	}
+
+	/**
+	 * Get desc. var separator.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getDescVarSeparator(): string {
+		return '; ';
+	}
+
+	/**
+	 * Get variant names. Overrides parent's implementation
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantNames(): array {
 		$names = [
 			'gan' => '原文',
 			'gan-hans' => '简体',
 			'gan-hant' => '繁體',
 		];
-		$this->mVariantNames = array_merge( $this->mVariantNames, $names );
+		return array_merge( parent::getVariantNames(), $names );
 	}
 
 	protected function loadDefaultTables() {
diff --git a/includes/language/converters/IuConverter.php b/includes/language/converters/IuConverter.php
index 9a480f66c9c..f3cb6d38f54 100644
--- a/includes/language/converters/IuConverter.php
+++ b/includes/language/converters/IuConverter.php
@@ -34,9 +34,6 @@
  * @ingroup Language
  */
 class IuConverter extends LanguageConverterSpecific {
-
-	protected $mDoContentConvert;
-
 	public $mToLatin = [
 		'ᐦ' => 'h', 'ᐃ' => 'i', 'ᐄ' => 'ii', 'ᐅ' => 'u', 'ᐆ' => 'uu', 'ᐊ' => 'a', 'ᐋ' => 'aa',
 		'ᑉ' => 'p', 'ᐱ' => 'pi', 'ᐲ' => 'pii', 'ᐳ' => 'pu', 'ᐴ' => 'puu', 'ᐸ' => 'pa', 'ᐹ' => 'paa',
@@ -89,18 +86,37 @@ class IuConverter extends LanguageConverterSpecific {
 	];
 
 	/**
-	 * @param Language $langobj
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'iu', 'ike-cans', 'ike-latn' ];
-		$variantfallbacks = [
+	public function getMainCode(): string {
+		return 'iu';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'iu', 'ike-cans', 'ike-latn' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'iu' => 'ike-cans',
 			'ike-cans' => 'iu',
 			'ike-latn' => 'iu',
 		];
-		$flags = [];
-
-		parent::__construct( $langobj, 'iu', $variants, $variantfallbacks, $flags );
 	}
 
 	protected function loadDefaultTables() {
diff --git a/includes/language/converters/KkConverter.php b/includes/language/converters/KkConverter.php
index 337eb5b5c1b..62eb9a0480c 100644
--- a/includes/language/converters/KkConverter.php
+++ b/includes/language/converters/KkConverter.php
@@ -36,14 +36,42 @@ define( 'H_HAMZA', 'ٴ' ); # U+0674 ARABIC LETTER HIGH HAMZA
  */
 class KkConverter extends LanguageConverterSpecific {
 
-	protected $mCyrl2Latn, $mLatn2Cyrl, $mCyLa2Arab;
+	/**
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getMainCode(): string {
+		return 'kk';
+	}
 
 	/**
-	 * @param Language $langobj
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'kk', 'kk-cyrl', 'kk-latn', 'kk-arab', 'kk-kz', 'kk-tr', 'kk-cn' ];
-		$variantfallbacks = [
+	public function getLanguageVariants(): array {
+		return [
+			'kk',
+			'kk-cyrl',
+			'kk-latn',
+			'kk-arab',
+			'kk-kz',
+			'kk-tr',
+			'kk-cn'
+		];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'kk' => 'kk-cyrl',
 			'kk-cyrl' => 'kk',
 			'kk-latn' => 'kk',
@@ -52,14 +80,6 @@ class KkConverter extends LanguageConverterSpecific {
 			'kk-tr' => 'kk-latn',
 			'kk-cn' => 'kk-arab'
 		];
-
-		parent::__construct( $langobj, 'kk',
-			$variants, $variantfallbacks, [] );
-
-		// No point delaying this since they're in code.
-		// Waiting until loadDefaultTables() means they never get loaded
-		// when the tables themselves are loaded from cache.
-		$this->loadRegs();
 	}
 
 	protected function loadDefaultTables() {
@@ -90,8 +110,14 @@ class KkConverter extends LanguageConverterSpecific {
 		$this->mTables['kk-cn']->merge( $this->mTables['kk-arab'] );
 	}
 
-	private function loadRegs() {
-		$this->mCyrl2Latn = [
+	/**
+	 * Return cyrillic to latin reg conversion table
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	protected function getMCyrl2Latn(): array {
+		return [
 			# # Punctuation
 			'/№/u' => 'No.',
 			# # Е after vowels
@@ -129,8 +155,16 @@ class KkConverter extends LanguageConverterSpecific {
 			'/Ш/u' => 'Ş', '/ш/u' => 'ş', '/Ы/u' => 'I', '/ы/u' => 'ı',
 			'/І/u' => 'İ', '/і/u' => 'i', '/Э/u' => 'É', '/э/u' => 'é',
 		];
+	}
 
-		$this->mLatn2Cyrl = [
+	/**
+	 * Return latin to cyrillic reg conversion table
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	protected function getMLatn2Cyrl(): array {
+		return [
 			# # Punctuation
 			'/#|No\./' => '№',
 			# # Şç
@@ -168,8 +202,16 @@ class KkConverter extends LanguageConverterSpecific {
 			'/W/u' => 'У', '/w/u' => 'у', '/Ý/u' => 'Й', '/ý/u' => 'й',
 			'/X/u' => 'Х', '/x/u' => 'х', '/Z/u' => 'З', '/z/u' => 'з',
 		];
+	}
 
-		$this->mCyLa2Arab = [
+	/**
+	 * Return latin or cyrillic to arab reg conversion table.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getMCyLa2Arab() {
+		return [
 			# # Punctuation -> Arabic
 			'/#|№|No\./u' => '؀', # U+0600
 			'/\,/' => '،', # U+060C
@@ -304,19 +346,22 @@ class KkConverter extends LanguageConverterSpecific {
 					$mstart = $m[1] + strlen( $m[0] );
 				}
 				$text =& $ret;
-				foreach ( $this->mCyLa2Arab as $pat => $rep ) {
+				$mCyLa2Arab = $this->getMCyLa2Arab();
+				foreach ( $mCyLa2Arab as $pat => $rep ) {
 					$text = preg_replace( $pat, $rep, $text );
 				}
 				return $text;
 			case 'kk-latn':
 			case 'kk-tr':
-				foreach ( $this->mCyrl2Latn as $pat => $rep ) {
+				$mCyrl2Latn = $this->getMCyrl2Latn();
+				foreach ( $mCyrl2Latn as $pat => $rep ) {
 					$text = preg_replace( $pat, $rep, $text );
 				}
 				return $text;
 			case 'kk-cyrl':
 			case 'kk-kz':
-				foreach ( $this->mLatn2Cyrl as $pat => $rep ) {
+				$mLatn2Cyrl = $this->getMLatn2Cyrl();
+				foreach ( $mLatn2Cyrl as $pat => $rep ) {
 					$text = preg_replace( $pat, $rep, $text );
 				}
 				return $text;
diff --git a/includes/language/converters/KuConverter.php b/includes/language/converters/KuConverter.php
index 3828e95287c..5c30e3b08c8 100644
--- a/includes/language/converters/KuConverter.php
+++ b/includes/language/converters/KuConverter.php
@@ -151,17 +151,37 @@ class KuConverter extends LanguageConverterSpecific {
 		];
 
 	/**
-	 * @param Language $langobj
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'ku', 'ku-arab', 'ku-latn' ];
-		$variantfallbacks = [
+	public function getMainCode(): string {
+		return 'ku';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'ku', 'ku-arab', 'ku-latn' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'ku' => 'ku-latn',
 			'ku-arab' => 'ku-latn',
 			'ku-latn' => 'ku-arab',
 		];
-
-		parent::__construct( $langobj, 'ku', $variants, $variantfallbacks );
 	}
 
 	protected function loadDefaultTables() {
diff --git a/includes/language/converters/ShiConverter.php b/includes/language/converters/ShiConverter.php
index 26034d28691..b5a50d4cb35 100644
--- a/includes/language/converters/ShiConverter.php
+++ b/includes/language/converters/ShiConverter.php
@@ -34,9 +34,6 @@
  * @ingroup Language
  */
 class ShiConverter extends LanguageConverterSpecific {
-
-	protected $mDoContentConvert;
-
 	// The Tifinagh alphabet sequence is based on
 	// "Dictionnaire Général de la Langue Amazighe Informatisé"
 	// by IRCAM (https://tal.ircam.ma/dglai/lexieam.php, DGLAi),
@@ -155,18 +152,37 @@ class ShiConverter extends LanguageConverterSpecific {
 	];
 
 	/**
-	 * @param Language $langobj
+	 * Get main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'shi', 'shi-tfng', 'shi-latn' ];
-		$variantfallbacks = [
+	public function getMainCode(): string {
+		return 'shi';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'shi', 'shi-tfng', 'shi-latn' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'shi' => 'shi-tfng',
 			'shi-tfng' => 'shi',
 			'shi-latn' => 'shi',
 		];
-
-		$flags = [];
-		parent::__construct( $langobj, 'shi', $variants, $variantfallbacks, $flags );
 	}
 
 	protected function loadDefaultTables() {
diff --git a/includes/language/converters/SrConverter.php b/includes/language/converters/SrConverter.php
index a3461fa75f9..1e01fcd23c9 100644
--- a/includes/language/converters/SrConverter.php
+++ b/includes/language/converters/SrConverter.php
@@ -75,21 +75,56 @@ class SrConverter extends LanguageConverterSpecific {
 	];
 
 	/**
-	 * @param Language $langobj
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'sr', 'sr-ec', 'sr-el' ];
-		$variantfallbacks = [
+	public function getMainCode(): string {
+		return 'sr';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'sr', 'sr-ec', 'sr-el' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'sr' => 'sr-ec',
 			'sr-ec' => 'sr',
 			'sr-el' => 'sr',
 		];
+	}
 
-		$flags = [
-			'S' => 'S', 'писмо' => 'S', 'pismo' => 'S',
-			'W' => 'W', 'реч' => 'W', 'reč' => 'W', 'ријеч' => 'W', 'riječ' => 'W'
+	/**
+	 * Get strings that maps to the flags.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	protected function getAdditionalFlags(): array {
+		return [
+			'S' => 'S',
+			'писмо' => 'S',
+			'pismo' => 'S',
+			'W' => 'W',
+			'реч' => 'W',
+			'reč' => 'W',
+			'ријеч' => 'W',
+			'riječ' => 'W'
 		];
-		parent::__construct( $langobj, 'sr', $variants, $variantfallbacks, $flags );
 	}
 
 	protected function loadDefaultTables() {
@@ -162,5 +197,4 @@ class SrConverter extends LanguageConverterSpecific {
 			return false;
 		}
 	}
-
 }
diff --git a/includes/language/converters/TgConverter.php b/includes/language/converters/TgConverter.php
index 1f31377d24c..a16c90650a4 100644
--- a/includes/language/converters/TgConverter.php
+++ b/includes/language/converters/TgConverter.php
@@ -27,6 +27,10 @@
  * @ingroup Language
  */
 class TgConverter extends LanguageConverter {
+
+	/**
+	 * @var array
+	 */
 	private $table = [
 		'а' => 'a',
 		'б' => 'b',
@@ -104,11 +108,33 @@ class TgConverter extends LanguageConverter {
 	];
 
 	/**
-	 * @param Language $langobj
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'tg', 'tg-latn' ];
-		parent::__construct( $langobj, 'tg', $variants );
+	public function getMainCode(): string {
+		return 'tg';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'tg', 'tg-latn' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [];
 	}
 
 	protected function loadDefaultTables() {
diff --git a/includes/language/converters/UzConverter.php b/includes/language/converters/UzConverter.php
index 186664cc82c..32bb77c22ba 100644
--- a/includes/language/converters/UzConverter.php
+++ b/includes/language/converters/UzConverter.php
@@ -103,16 +103,37 @@ class UzConverter extends LanguageConverter {
 	];
 
 	/**
-	 * @param Language $langobj
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
 	 */
-	public function __construct( $langobj ) {
-		$variants = [ 'uz', 'uz-latn', 'uz-cyrl' ];
-		$variantfallbacks = [
+	public function getMainCode(): string {
+		return 'uz';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'uz', 'uz-latn', 'uz-cyrl' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
 			'uz' => 'uz-latn',
 			'uz-cyrl' => 'uz',
 			'uz-latn' => 'uz',
 		];
-		parent::__construct( $langobj, 'uz', $variants, $variantfallbacks );
 	}
 
 	protected function loadDefaultTables() {
@@ -123,6 +144,11 @@ class UzConverter extends LanguageConverter {
 		];
 	}
 
+	/**
+	 * @param string $text
+	 * @param string $toVariant
+	 * @return string
+	 */
 	public function translate( $text, $toVariant ) {
 		if ( $toVariant == 'uz-cyrl' ) {
 			$text = str_replace( 'ye', 'е', $text );
@@ -134,5 +160,4 @@ class UzConverter extends LanguageConverter {
 		}
 		return parent::translate( $text, $toVariant );
 	}
-
 }
diff --git a/includes/language/converters/ZhConverter.php b/includes/language/converters/ZhConverter.php
index 11e596546e4..91723df5a9d 100644
--- a/includes/language/converters/ZhConverter.php
+++ b/includes/language/converters/ZhConverter.php
@@ -25,14 +25,25 @@
  * @ingroup Language
  */
 class ZhConverter extends LanguageConverter {
-	/**
-	 * @param Language $langobj
-	 */
-	public function __construct( $langobj ) {
-		$this->mDescCodeSep = '：';
-		$this->mDescVarSep = '；';
 
-		$variants = [
+	/**
+	 * Get Main language code.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getMainCode(): string {
+		return 'zh';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [
 			'zh',
 			'zh-hans',
 			'zh-hant',
@@ -43,9 +54,26 @@ class ZhConverter extends LanguageConverter {
 			'zh-sg',
 			'zh-tw'
 		];
+	}
 
-		$variantfallbacks = [
-			'zh' => [ 'zh-hans', 'zh-hant', 'zh-cn', 'zh-tw', 'zh-hk', 'zh-sg', 'zh-mo', 'zh-my' ],
+	/**
+	 * Get language variants fallbacks.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [
+			'zh' => [
+				'zh-hans',
+				'zh-hant',
+				'zh-cn',
+				'zh-tw',
+				'zh-hk',
+				'zh-sg',
+				'zh-mo',
+				'zh-my'
+			],
 			'zh-hans' => [ 'zh-cn', 'zh-sg', 'zh-my' ],
 			'zh-hant' => [ 'zh-tw', 'zh-hk', 'zh-mo' ],
 			'zh-cn' => [ 'zh-hans', 'zh-sg', 'zh-my' ],
@@ -55,17 +83,49 @@ class ZhConverter extends LanguageConverter {
 			'zh-hk' => [ 'zh-hant', 'zh-mo', 'zh-tw' ],
 			'zh-mo' => [ 'zh-hant', 'zh-hk', 'zh-tw' ],
 		];
-		$ml = [
+	}
+
+	/**
+	 * Get manual level limits for variants supported by converter.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getAdditionalManualLevel(): array {
+		return [
 			'zh' => 'disable',
 			'zh-hans' => 'unidirectional',
 			'zh-hant' => 'unidirectional',
 		];
+	}
 
-		parent::__construct( $langobj, 'zh',
-			$variants,
-			$variantfallbacks,
-			[],
-			$ml );
+	/**
+	 * Get desc. code separator.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getDescCodeSeparator(): string {
+		return '：';
+	}
+
+	/**
+	 * Get desc. var separator.
+	 * @since 1.36
+	 *
+	 * @return string
+	 */
+	public function getDescVarSeparator(): string {
+		return '；';
+	}
+
+	/**
+	 * Get variant names.
+	 * @since 1.36
+	 *
+	 * @return array
+	 */
+	public function getVariantNames(): array {
 		$names = [
 			'zh' => '原文',
 			'zh-hans' => '简体',
@@ -77,7 +137,7 @@ class ZhConverter extends LanguageConverter {
 			'zh-sg' => '新加坡',
 			'zh-my' => '大马',
 		];
-		$this->mVariantNames = array_merge( $this->mVariantNames, $names );
+		return array_merge( parent::getVariantNames(), $names );
 	}
 
 	protected function loadDefaultTables() {
diff --git a/tests/phpunit/includes/debug/DeprecationHelperTest.php b/tests/phpunit/includes/debug/DeprecationHelperTest.php
index c186a7001c2..1589a765047 100644
--- a/tests/phpunit/includes/debug/DeprecationHelperTest.php
+++ b/tests/phpunit/includes/debug/DeprecationHelperTest.php
@@ -37,6 +37,10 @@ class DeprecationHelperTest extends MediaWikiIntegrationTestCase {
 
 	public function provideGet() {
 		return [
+			[ 'protectedDeprecated', 0, null ],
+			[ 'privateDeprecated', null, null ],
+			[ 'fallbackDeprecated', null, null ],
+			[ 'fallbackGetterOnly', null, null ],
 			[ 'protectedNonDeprecated', E_USER_ERROR,
 				'Cannot access non-public property TestDeprecatedClass::$protectedNonDeprecated' ],
 			[ 'privateNonDeprecated', E_USER_ERROR,
@@ -69,6 +73,11 @@ class DeprecationHelperTest extends MediaWikiIntegrationTestCase {
 
 	public function provideSet() {
 		return [
+			[ 'protectedDeprecated', null, null ],
+			[ 'privateDeprecated', null, null ],
+			[ 'fallbackDeprecated', null, null ],
+			[ 'fallbackGetterOnly', E_USER_ERROR,
+			  'Cannot access non-public property TestDeprecatedClass::$fallbackGetterOnly' ],
 			[ 'protectedNonDeprecated', E_USER_ERROR,
 			  'Cannot access non-public property TestDeprecatedClass::$protectedNonDeprecated' ],
 			[ 'privateNonDeprecated', E_USER_ERROR,
@@ -146,10 +155,8 @@ class DeprecationHelperTest extends MediaWikiIntegrationTestCase {
 	}
 
 	protected function assertDeprecationWarningIssued( callable $callback ) {
-		MWDebug::clearLog();
+		$this->expectDeprecation();
 		$callback();
-		$wrapper = TestingAccessWrapper::newFromClass( MWDebug::class );
-		$this->assertNotEmpty( $wrapper->deprecationWarnings );
 	}
 
 	/**
diff --git a/tests/phpunit/includes/debug/TestDeprecatedClass.php b/tests/phpunit/includes/debug/TestDeprecatedClass.php
index 5a9e645b821..634b6cab3af 100644
--- a/tests/phpunit/includes/debug/TestDeprecatedClass.php
+++ b/tests/phpunit/includes/debug/TestDeprecatedClass.php
@@ -8,12 +8,25 @@ class TestDeprecatedClass {
 	protected $protectedNonDeprecated = 1;
 	private $privateDeprecated = 1;
 	private $privateNonDeprecated = 1;
+	private $fallbackDeprecated = 1;
 
 	public function __construct() {
-		$this->deprecatedPublicProperties = [
-			'protectedDeprecated' => '1.23',
-			'privateDeprecated' => '1.24',
-		];
+		$this->deprecatePublicProperty( 'protectedDeprecated', '1.23' );
+		$this->deprecatePublicProperty( 'privateDeprecated', '1.24' );
+
+		$this->deprecatePublicPropertyFallback( 'fallbackDeprecated', '1.25',
+			function () {
+				return $this->fallbackDeprecated;
+			},
+			function ( $value ) {
+				$this->fallbackDeprecated = $value;
+			}
+		);
+		$this->deprecatePublicPropertyFallback( 'fallbackGetterOnly', '1.25',
+			function () {
+				return 1;
+			}
+		);
 	}
 
 	public function setThings( $prod, $prond, $prid, $prind ) {
diff --git a/tests/phpunit/languages/LanguageConverterFactoryTest.php b/tests/phpunit/languages/LanguageConverterFactoryTest.php
index d339e8d45f4..75ec5a84990 100644
--- a/tests/phpunit/languages/LanguageConverterFactoryTest.php
+++ b/tests/phpunit/languages/LanguageConverterFactoryTest.php
@@ -167,12 +167,12 @@ class LanguageConverterFactoryTest extends MediaWikiLangTestCase {
 			$testConverter = TestingAccessWrapper::newFromObject( $converter );
 			$this->assertSame( $lang, $testConverter->mLangObj, "Language should be as provided" );
 
-			$this->assertEquals( $code, $testConverter->mMainLanguageCode,
+			$this->assertEquals( $code, $testConverter->getMainCode(),
 				"mMainLanguageCode should be as $code" );
-			$this->assertEquals( $manualLevel, $testConverter->mManualLevel, "Manual Level" );
+			$this->assertEquals( $manualLevel, $testConverter->getManualLevel(), "Manual Level" );
 
-			$this->assertEquals( $variants, $testConverter->mVariants, "Variants" );
-			$this->assertEquals( $variantFallbacks, $testConverter->mVariantFallbacks, "Variant Fallbacks" );
+			$this->assertEquals( $variants, $testConverter->getVariants(), "Variants" );
+			$this->assertEquals( $variantFallbacks, $testConverter->getVariantsFallbacks(), "Variant Fallbacks" );
 			$defaultFlags = [
 				'A' => 'A',
 				'T' => 'T',
@@ -184,7 +184,7 @@ class LanguageConverterFactoryTest extends MediaWikiLangTestCase {
 			];
 			$this->assertArraySubmapSame(
 				array_merge( $defaultFlags, $flags ),
-				$converter->mFlags,
+				$converter->getFlags(),
 				"Flags"
 			);
 		}
diff --git a/tests/phpunit/languages/LanguageConverterTest.php b/tests/phpunit/languages/LanguageConverterTest.php
index 21dfc4aa610..b2a83d10506 100644
--- a/tests/phpunit/languages/LanguageConverterTest.php
+++ b/tests/phpunit/languages/LanguageConverterTest.php
@@ -39,12 +39,7 @@ class LanguageConverterTest extends MediaWikiLangTestCase {
 		} ) );
 		$this->lang->expects( $this->never() )
 			->method( $this->anythingBut( 'factory', 'getNsText', 'ucfirst' ) );
-		$this->lc = new DummyConverter(
-			$this->lang, 'tg',
-			# Adding 'sgs' as a variant to ensure we handle deprecated codes
-			# adding 'simple' as a variant to ensure we handle non BCP 47 codes
-			[ 'tg', 'tg-latn', 'sgs', 'simple' ]
-		);
+		$this->lc = new DummyConverter( $this->lang );
 	}
 
 	protected function tearDown() : void {
diff --git a/tests/phpunit/mocks/languages/DummyConverter.php b/tests/phpunit/mocks/languages/DummyConverter.php
index d00218da4e5..45dfd8a2fb3 100644
--- a/tests/phpunit/mocks/languages/DummyConverter.php
+++ b/tests/phpunit/mocks/languages/DummyConverter.php
@@ -5,12 +5,42 @@
  */
 class DummyConverter extends LanguageConverter {
 
+	/**
+	 * @var array
+	 */
 	private $table = [
 		'б' => 'b',
 		'в' => 'v',
 		'г' => 'g',
 	];
 
+	/**
+	 * Get Main language code.
+	 *
+	 * @return string
+	 */
+	public function getMainCode(): string {
+		return 'tg';
+	}
+
+	/**
+	 * Get supported variants of the language.
+	 *
+	 * @return array
+	 */
+	public function getLanguageVariants(): array {
+		return [ 'tg', 'tg-latn', 'sgs', 'simple' ];
+	}
+
+	/**
+	 * Get language variants fallbacks.
+	 *
+	 * @return array
+	 */
+	public function getVariantsFallbacks(): array {
+		return [];
+	}
+
 	public function loadDefaultTables() {
 		$this->mTables = [
 			'sgs' => new ReplacementArray(),