diff --git a/includes/installer/Installer.php b/includes/installer/Installer.php
index 367149d2477..0f8a5b092cc 100644
--- a/includes/installer/Installer.php
+++ b/includes/installer/Installer.php
@@ -454,6 +454,7 @@ abstract class Installer {
 
 		$this->parserTitle = Title::newFromText( 'Installer' );
 		$this->parserOptions = new ParserOptions( $wgUser ); // language will be wrong :(
+		$this->parserOptions->setTidy( true );
 		// Don't try to access DB before user language is initialised
 		$this->setParserLanguage( Language::factory( 'en' ) );
 	}
diff --git a/includes/installer/WebInstallerDocument.php b/includes/installer/WebInstallerDocument.php
index fc1c33f9b9c..43fe7483c5f 100644
--- a/includes/installer/WebInstallerDocument.php
+++ b/includes/installer/WebInstallerDocument.php
@@ -29,7 +29,7 @@ abstract class WebInstallerDocument extends WebInstallerPage {
 	public function execute() {
 		$text = $this->getFileContents();
 		$text = InstallDocFormatter::format( $text );
-		$this->parent->output->addWikiText( $text );
+		$this->parent->output->addWikiTextInterface( $text );
 		$this->startForm();
 		$this->endForm( false );
 	}
diff --git a/includes/installer/WebInstallerOutput.php b/includes/installer/WebInstallerOutput.php
index cb0092d2a6e..dd76ce9242f 100644
--- a/includes/installer/WebInstallerOutput.php
+++ b/includes/installer/WebInstallerOutput.php
@@ -89,8 +89,17 @@ class WebInstallerOutput {
 
 	/**
 	 * @param string $text
+	 * @deprecated since 1.32; use addWikiTextInterface instead
 	 */
 	public function addWikiText( $text ) {
+		wfDeprecated( __METHOD__, '1.32' );
+		$this->addWikiTextInterface( $text );
+	}
+
+	/**
+	 * @param string $text
+	 */
+	public function addWikiTextInterface( $text ) {
 		$this->addHTML( $this->parent->parse( $text ) );
 	}
 
diff --git a/includes/installer/WebInstallerWelcome.php b/includes/installer/WebInstallerWelcome.php
index 44ff0bb2183..0d7948495ee 100644
--- a/includes/installer/WebInstallerWelcome.php
+++ b/includes/installer/WebInstallerWelcome.php
@@ -30,12 +30,12 @@ class WebInstallerWelcome extends WebInstallerPage {
 				return 'continue';
 			}
 		}
-		$this->parent->output->addWikiText( wfMessage( 'config-welcome' )->plain() );
+		$this->parent->output->addWikiTextInterface( wfMessage( 'config-welcome' )->plain() );
 		$status = $this->parent->doEnvironmentChecks();
 		if ( $status->isGood() ) {
 			$this->parent->output->addHTML( '<span class="success-message">' .
 				wfMessage( 'config-env-good' )->escaped() . '</span>' );
-			$this->parent->output->addWikiText( wfMessage( 'config-copyright',
+			$this->parent->output->addWikiTextInterface( wfMessage( 'config-copyright',
 				SpecialVersion::getCopyrightAndAuthorList() )->plain() );
 			$this->startForm();
 			$this->endForm();