diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index 8791a941453..505907de299 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -4425,20 +4425,24 @@ $wgResourceLoaderSources = [];
 $wgResourceBasePath = null;
 
 /**
- * Maximum time in seconds to cache resources served by ResourceLoader.
- * Used to set last modified headers (max-age/s-maxage).
+ * How long a CDN or browser may cache a ResourceLoader HTTP response.
  *
- * Following options to distinguish:
- * - versioned: Used for modules with a version, because changing version
- *   numbers causes cache misses. This normally has a long expiry time.
- * - unversioned: Used for modules without a version to propagate changes
- *   quickly to clients. Also used for modules with errors to recover quickly.
- *   This normally has a short expiry time.
+ * Maximum time in seconds. Used for the `max-age` and `s-maxage` Cache-Control
+ * headers.
  *
- * Expiry time for the options to distinguish:
- * - server: Squid/Varnish but also any other public proxy cache between the
- *   client and MediaWiki.
- * - client: On the client side (e.g. in the browser cache).
+ * Valid keys:
+ *
+ * - versioned: Used for URLs carrying a "version" parameter.
+ *   This applies to the bulk of load.php transfers, and may have a long cache
+ *   duration (e.g. weeks or months), because a change in the module bundle will
+ *   naturally produce a different URL and thus automatically bust the cache.
+ *
+ * - unversioned: Used for URLs that must not carry a "version" parameter.
+ *   This includes the startup manifest and controls how quickly changes (in
+ *   the module registry, dependency tree, and module version) will propagate
+ *   to clients. This should have a short cache duration (e.g. minutes).
+ *
+ * @since 1.35
  */
 $wgResourceLoaderMaxage = [
 	'versioned' => 30 * 24 * 60 * 60, // 30 days
diff --git a/includes/resourceloader/ResourceLoader.php b/includes/resourceloader/ResourceLoader.php
index 359b4fe6747..680f030b316 100644
--- a/includes/resourceloader/ResourceLoader.php
+++ b/includes/resourceloader/ResourceLoader.php
@@ -57,62 +57,54 @@ use Wikimedia\WrappedString;
  * @since 1.17
  */
 class ResourceLoader implements LoggerAwareInterface {
-	/** @var Config */
-	protected $config;
-	/** @var MessageBlobStore */
-	protected $blobStore;
-	/** @var DependencyStore */
-	protected $depStore;
+	/** @var int */
+	public const CACHE_VERSION = 9;
+	/** @var string JavaScript / CSS pragma to disable minification. * */
+	public const FILTER_NOMIN = '/*@nomin*/';
 
-	/** @var LoggerInterface */
-	private $logger;
-
-	/** @var HookContainer */
-	private $hookContainer;
-
-	/** @var HookRunner */
-	private $hookRunner;
-
-	/** @var ResourceLoaderModule[] Map of (module name => ResourceLoaderModule) */
-	protected $modules = [];
-	/** @var array[] Map of (module name => associative info array) */
-	protected $moduleInfos = [];
-	/**
-	 * Associative array mapping framework ids to a list of names of test suite modules
-	 * like [ 'qunit' => [ 'mediawiki.tests.qunit.suites', 'ext.foo.tests', ... ], ... ]
-	 * @var array
-	 */
-	protected $testModuleNames = [];
-	/** @var string[] List of module names that contain QUnit test suites */
-	protected $testSuiteModuleNames = [];
-	/** @var array Map of (source => path); E.g. [ 'source-id' => 'http://.../load.php' ] */
-	protected $sources = [];
-	/** @var array Errors accumulated during current respond() call */
-	protected $errors = [];
-	/** @var string[] Extra HTTP response headers from modules loaded in makeModuleResponse() */
-	protected $extraHeaders = [];
-
-	/** @var array Map of (module-variant => buffered DependencyStore updates) */
-	private $depStoreUpdateBuffer = [];
-
-	/** @var array Styles that are skin-specific and supplement or replace the
-	 * default skinStyles of a FileModule. See $wgResourceModuleSkinStyles.
-	 */
-	private $moduleSkinStyles = [];
+	/** @var string */
+	private const RL_DEP_STORE_PREFIX = 'ResourceLoaderModule';
+	/** @var int How long to preserve indirect dependency metadata in our backend store. */
+	private const RL_MODULE_DEP_TTL = BagOStuff::TTL_WEEK;
 
 	/** @var int|null */
 	protected static $debugMode = null;
 
-	/** @var int */
-	public const CACHE_VERSION = 9;
+	/** @var Config */
+	private $config;
+	/** @var MessageBlobStore */
+	private $blobStore;
+	/** @var DependencyStore */
+	private $depStore;
+	/** @var LoggerInterface */
+	private $logger;
+	/** @var HookContainer */
+	private $hookContainer;
+	/** @var HookRunner */
+	private $hookRunner;
 
-	/** @var string */
-	private const RL_DEP_STORE_PREFIX = 'ResourceLoaderModule';
-	/** @var int Expiry (in seconds) of indirect dependency information for modules */
-	private const RL_MODULE_DEP_TTL = BagOStuff::TTL_WEEK;
-
-	/** @var string JavaScript / CSS pragma to disable minification. * */
-	public const FILTER_NOMIN = '/*@nomin*/';
+	/** @var ResourceLoaderModule[] Map of (module name => ResourceLoaderModule) */
+	private $modules = [];
+	/** @var array[] Map of (module name => associative info array) */
+	private $moduleInfos = [];
+	/** @var string[] List of module names that contain QUnit test suites */
+	private $testSuiteModuleNames = [];
+	/** @var string[] Map of (source => path); E.g. [ 'source-id' => 'http://.../load.php' ] */
+	private $sources = [];
+	/** @var array Errors accumulated during a respond() call. Exposed for testing. */
+	protected $errors = [];
+	/**
+	 * @var string[] Buffer for extra response headers during a makeModuleResponse() call.
+	 * Exposed for testing.
+	 */
+	protected $extraHeaders = [];
+	/** @var array Map of (module-variant => buffered DependencyStore updates) */
+	private $depStoreUpdateBuffer = [];
+	/**
+	 * @var array Styles that are skin-specific and supplement or replace the
+	 * default skinStyles of a FileModule. See $wgResourceModuleSkinStyles.
+	 */
+	private $moduleSkinStyles = [];
 
 	/**
 	 * Load information stored in the database and dependency tracking store about modules
@@ -238,8 +230,11 @@ class ResourceLoader implements LoggerAwareInterface {
 	}
 
 	/**
-	 * Register core modules and runs registration hooks.
-	 * @param Config $config
+	 * @param Config $config Required configuration:
+	 *  - EnableJavaScriptTest
+	 *  - LoadScript
+	 *  - ResourceLoaderMaxage
+	 *  - UseFileCache
 	 * @param LoggerInterface|null $logger [optional]
 	 * @param DependencyStore|null $tracker [optional]
 	 */
@@ -248,11 +243,10 @@ class ResourceLoader implements LoggerAwareInterface {
 		LoggerInterface $logger = null,
 		DependencyStore $tracker = null
 	) {
-		$this->logger = $logger ?: new NullLogger();
-		$services = MediaWikiServices::getInstance();
-
 		$this->config = $config;
+		$this->logger = $logger ?: new NullLogger();
 
+		$services = MediaWikiServices::getInstance();
 		$this->hookContainer = $services->getHookContainer();
 		$this->hookRunner = new HookRunner( $this->hookContainer );
 
diff --git a/tests/phpunit/ResourceLoaderTestCase.php b/tests/phpunit/ResourceLoaderTestCase.php
index d17822b0398..1ca47d2149c 100644
--- a/tests/phpunit/ResourceLoaderTestCase.php
+++ b/tests/phpunit/ResourceLoaderTestCase.php
@@ -56,8 +56,12 @@ abstract class ResourceLoaderTestCase extends MediaWikiIntegrationTestCase {
 
 	public static function getSettings() {
 		return [
-			// For ResourceLoader::inDebugMode since it doesn't have context
+			// For ResourceLoader class
 			'ResourceLoaderDebug' => true,
+			'LoadScript' => '/w/load.php',
+			'EnableJavaScriptTest' => false,
+			// For ResourceLoader::respond() - TODO: Inject somehow T32956
+			'UseFileCache' => false,
 
 			// For ResourceLoaderModule
 			'ResourceLoaderValidateJS' => false,
@@ -71,17 +75,11 @@ abstract class ResourceLoaderTestCase extends MediaWikiIntegrationTestCase {
 			'ResourceBasePath' => '/w',
 			'ParserEnableLegacyMediaDOM' => true,
 
-			// For ResourceLoader::expandUrl()
+			// For  ResourceLoader::getSiteConfigSettings and ResourceLoaderStartUpModule
 			'Server' => 'https://example.org',
-			// For ResourceLoaderStartUpModule and ResourceLoader::__construct()
 			'ScriptPath' => '/w',
 			'Script' => '/w/index.php',
-			'LoadScript' => '/w/load.php',
-			'EnableJavaScriptTest' => false,
 			'ResourceLoaderEnableJSProfiler' => false,
-
-			// For ResourceLoader::respond() - TODO: Inject somehow T32956
-			'UseFileCache' => false,
 		];
 	}