diff --git a/includes/PopupsHooks.php b/includes/PopupsHooks.php
index 6b2772c18..39a142e54 100644
--- a/includes/PopupsHooks.php
+++ b/includes/PopupsHooks.php
@@ -104,11 +104,20 @@ class PopupsHooks {
 	}
 
 	/**
+	 * Hook handler for the ResourceLoaderStartUpModule that makes static configuration visible to
+	 * the frontend. These variables end in the only "startup" ResourceLoader module that is loaded
+	 * before all others.
+	 *
+	 * Dynamic configuration that depends on the context needs to be published via the
+	 * MakeGlobalVariablesScript hook.
+	 *
 	 * @param array &$vars Array of variables to be added into the output of the startup module
+	 * @param string $skin
 	 */
-	public static function onResourceLoaderGetConfigVars( array &$vars ) {
+	public static function onResourceLoaderGetConfigVars( array &$vars, $skin ) {
 		/** @var \Config $config */
 		$config = MediaWikiServices::getInstance()->getService( 'Popups.Config' );
+
 		$vars['wgPopupsVirtualPageViews'] = $config->get( 'PopupsVirtualPageViews' );
 		$vars['wgPopupsGateway'] = $config->get( 'PopupsGateway' );
 		$vars['wgPopupsEventLogging'] = $config->get( 'PopupsEventLogging' );
@@ -117,7 +126,8 @@ class PopupsHooks {
 	}
 
 	/**
-	 * MakeGlobalVariablesScript hook handler.
+	 * Hook handler publishing dynamic configuration that depends on the context, e.g. the page or
+	 * the users settings. These variables end in an inline <script> in the documents head.
 	 *
 	 * Variables added:
 	 * * `wgPopupsReferencePreviews' - The server's notion of whether or not the reference
@@ -130,9 +140,9 @@ class PopupsHooks {
 	 *   user has enabled conflicting Navigational Popups Gadget.
 	 *
 	 * @param array &$vars variables to be added into the output of OutputPage::headElement
-	 * @param OutputPage $out OutputPage instance calling the hook
+	 * @param \IContextSource $out OutputPage instance calling the hook
 	 */
-	public static function onMakeGlobalVariablesScript( array &$vars, OutputPage $out ) {
+	public static function onMakeGlobalVariablesScript( array &$vars, \IContextSource $out ) {
 		/** @var PopupsContext $context */
 		$context = MediaWikiServices::getInstance()->getService( 'Popups.Context' );
 		/** @var \Config $config */
@@ -142,7 +152,8 @@ class PopupsHooks {
 		$vars['wgPopupsReferencePreviews'] = self::isReferencePreviewsEnabled( $user, $config );
 		$vars['wgPopupsShouldSendModuleToUser'] = $context->shouldSendModuleToUser( $user );
 		$vars['wgPopupsConflictsWithNavPopupGadget'] = $context->conflictsWithNavPopupsGadget(
-			$user );
+			$user
+		);
 	}
 
 	/**
@@ -166,7 +177,7 @@ class PopupsHooks {
 	 *
 	 * @param array &$wgDefaultUserOptions Reference to default options array
 	 */
-	public static function onUserGetDefaultOptions( &$wgDefaultUserOptions ) {
+	public static function onUserGetDefaultOptions( array &$wgDefaultUserOptions ) {
 		/** @var \Config $config */
 		$config = MediaWikiServices::getInstance()->getService( 'Popups.Config' );
 
diff --git a/tests/phpunit/PopupsHooksTest.php b/tests/phpunit/PopupsHooksTest.php
index 13443f13b..74a3e4b77 100644
--- a/tests/phpunit/PopupsHooksTest.php
+++ b/tests/phpunit/PopupsHooksTest.php
@@ -174,7 +174,7 @@ class PopupsHooksTest extends MediaWikiTestCase {
 			'wgPopupsStatsvSamplingRate' => 0
 		];
 		$this->setMwGlobals( $config );
-		PopupsHooks::onResourceLoaderGetConfigVars( $vars );
+		PopupsHooks::onResourceLoaderGetConfigVars( $vars, '' );
 		$this->assertCount( 6, $vars, 'A configuration is retrieved.' );
 
 		foreach ( $config as $key => $value ) {