[Firefox] Loading user.css from file doesn't work anymore

[rRobis]

Installation page doesn't open anymore when dropping the user.css files into address bar.

System Information

• OS: Windows 11 latest
• Browser: Firefox 135.0
• Stylus Version: 2.3.10 (2.3.12. i tried nightly, same problem) (in older 2.1.0 version it seems to open but not completely, maybe because it's installed as temporary add-on. I remember not long ago it was still working)

New FF profile acts the same.

Trying to load default template or any other user.css file

/* ==UserStyle==
@name           Testing
@namespace      github.com/openstyles/stylus
@version        1.0.0
@description    A new userstyle
@author         Me
==/UserStyle== */

@-moz-document domain("example.com") {
    /* Insert code here... */
}

Stylus debugging console shows:

Uncaught (in promise) Error: Script 'moz-extension://107005a7-d610-486f-ae8d-18955eae3ece/js/install-hook-usercss.js' result is non-structured-clonable data 2 install-hook-usercss.js
    maybeInstall moz-extension://107005a7-d610-486f-ae8d-18955eae3ece/js/background.js:1
    InterpretGeneratorResume self-hosted:1413
    AsyncFunctionThrow self-hosted:804
    (Async: async)
    7402 moz-extension://107005a7-d610-486f-ae8d-18955eae3ece/js/background.js:1
    onNavigation moz-extension://107005a7-d610-486f-ae8d-18955eae3ece/js/background.js:1
    apply self-hosted:2285
    applySafeWithoutClone resource://gre/modules/ExtensionCommon.sys.mjs:677
    fire resource://gre/modules/ExtensionChild.sys.mjs:872
    recvRunListener resource://gre/modules/ExtensionChild.sys.mjs:876
    _recv resource://gre/modules/ConduitsChild.sys.mjs:90
    receiveMessage resource://gre/modules/ConduitsChild.sys.mjs:201

[tophf]

Until the fix is published the workaround is either to use a simple localhost http server or use the nightly build.