@dgrammatiko can you have a look at the translations in build/media_source/system/js/fields/calendar-locales the new translations are with the complete language codes and not only the 2 char codes.

https://github.com/joomla/core-translations/tree/main/joomla_v4/translations/core/build/media_source/system/js/fields/calendar-locales

I think the new codes are the right one but I'm not sure if the calendar field can load them, can you maybe update the code or a hint where I have to fix it?

can you maybe update the code or a hint where I have to fix it?

The code that handles the files is:
https://github.com/joomla/joomla-cms/blob/4.0-dev/libraries/src/WebAsset/AssetItem/LangActiveAssetItem.php

really funny, didn't know what .css is a language format ;-)

https://github.com/joomla/joomla-cms/blob/4.0-dev/libraries/src/WebAsset/AssetItem/LangActiveAssetItem.php#L52

I would expect that file is broken. Thanks for the help I will take a look

I would expect that file is broken. Thanks for the help I will take a look

I haven't looked at the logic but from the lang object, you can extract any possible format for the .js file, (maybe some fileExists are required but I sure you will figure it out)

Also one comment here on the github action: probably you want to scope the branch or you might ruin the 3.x branch

The action is only executed on the joomla-translation-bot account and in the translation branch
if: ${{ github.repository == 'joomla-translation-bot/joomla-cms' && github.ref == 'refs/heads/translation' }}

I'm not familiar mit github actions...