diff --git a/extension.json b/extension.json
index fe0baa8bc..faad23397 100644
--- a/extension.json
+++ b/extension.json
@@ -35,6 +35,9 @@
 		"MathAliasNoTranslate": "Math.alias.noTranslate.php"
 	},
 	"callback": "MediaWiki\\Extension\\Math\\Hooks::onConfig",
+	"ExtensionFunctions": [
+		"MediaWiki\\Extension\\Math\\Hooks::onExtensionFunctions"
+	],
 	"HookHandlers": {
 		"ParserHooksHandler": {
 			"class": "MediaWiki\\Extension\\Math\\HookHandlers\\ParserHooksHandler",
@@ -368,18 +371,5 @@
 	"ServiceWiringFiles": [
 		"ServiceWiring.php"
 	],
-	"RestRoutes": [
-		{
-			"path": "/math/v0/popup/html/{qid}",
-			"method": "GET",
-			"class": "MediaWiki\\Extension\\Math\\Rest\\Popup",
-			"services": [
-				"Math.WikibaseConnector",
-				"LanguageFactory",
-				"LanguageNameUtils",
-				"TitleFactory"
-			]
-		}
-	],
 	"manifest_version": 2
 }
diff --git a/popupRestRoutes.json b/popupRestRoutes.json
new file mode 100644
index 000000000..6ab53088c
--- /dev/null
+++ b/popupRestRoutes.json
@@ -0,0 +1,13 @@
+[
+	{
+		"path": "/math/v0/popup/html/{qid}",
+		"method": "GET",
+		"class": "MediaWiki\\Extension\\Math\\Rest\\Popup",
+		"services": [
+			"Math.WikibaseConnector",
+			"LanguageFactory",
+			"LanguageNameUtils",
+			"TitleFactory"
+		]
+	}
+]
diff --git a/src/Hooks.php b/src/Hooks.php
index f048df75c..db7fab63d 100644
--- a/src/Hooks.php
+++ b/src/Hooks.php
@@ -81,6 +81,13 @@ class Hooks implements
 		}
 	}
 
+	public static function onExtensionFunctions() {
+		if ( ExtensionRegistry::getInstance()->isLoaded( 'WikibaseClient' ) ) {
+			global $wgRestAPIAdditionalRouteFiles;
+			$wgRestAPIAdditionalRouteFiles[] = dirname( __DIR__ ) . '/popupRestRoutes.json';
+		}
+	}
+
 	/**
 	 * MaintenanceRefreshLinksInit handler; optimize settings for refreshLinks batch job.
 	 *