diff --git a/src/node/hooks/express/tests.js b/src/node/hooks/express/tests.js
index 5573b6251..1b1fe8f55 100644
--- a/src/node/hooks/express/tests.js
+++ b/src/node/hooks/express/tests.js
@@ -30,7 +30,7 @@ const findSpecs = async (specDir) => {
 };
 
 exports.expressCreateServer = (hookName, args, cb) => {
-  args.app.get('/tests/frontend/frontendTestSpecs.js', (req, res, next) => {
+  args.app.get('/tests/frontend/frontendTestSpecs.json', (req, res, next) => {
     (async () => {
       const modules = [];
       await Promise.all(Object.entries(plugins.plugins).map(async ([plugin, def]) => {
@@ -53,8 +53,7 @@ exports.expressCreateServer = (hookName, args, cb) => {
         return aCore ? 1 : -1;
       });
       console.debug('Sent browser the following test spec modules:', modules);
-      res.setHeader('content-type', 'application/javascript');
-      res.end(`window.frontendTestSpecs = ${JSON.stringify(modules, null, 2)};\n`);
+      res.json(modules);
     })().catch((err) => next(err || new Error(err)));
   });
 
diff --git a/src/tests/frontend/index.html b/src/tests/frontend/index.html
index 5c8f10206..178ba6030 100644
--- a/src/tests/frontend/index.html
+++ b/src/tests/frontend/index.html
@@ -23,7 +23,5 @@
     <script src="helper/methods.js"></script>
     <script src="helper/ui.js"></script>
     <script src="helper/multipleUsers.js"></script>
-
-    <script src="frontendTestSpecs.js"></script>
     <script src="runner.js"></script>
 </html>
diff --git a/src/tests/frontend/runner.js b/src/tests/frontend/runner.js
index c6d2d9072..3100b13df 100644
--- a/src/tests/frontend/runner.js
+++ b/src/tests/frontend/runner.js
@@ -149,7 +149,7 @@ $(() => (async () => {
   // asynchronous form of require()). In addition, the performance gains would be minimal because
   // require-kernel only loads 2 at a time by default. (Increasing the default could cause problems
   // because browsers like to limit the number of concurrent fetches.)
-  for (const spec of window.frontendTestSpecs) {
+  for (const spec of await $.getJSON('frontendTestSpecs.json')) {
     const desc = spec
         .replace(/^ep_etherpad-lite\/tests\/frontend\/specs\//, '<core> ')
         .replace(/^([^/ ]*)\/static\/tests\/frontend\/specs\//, '<$1> ');