I have checked all the files and realized that every file and folder is available except the "mage" folder. I use the
bin/magento s:s:d -f command.
So whats missing is
I have found a workaround by manually uploading the two mage folders from an old stage server into the static theme folders. Then both back- and frontend are fine. This however works only until the next static deployment of course...
I have already checked my file permissions, but since I did not change them, I don't think it has something to do with it.
When I try to open the files by URL as in this example
de_DE/mage/requirejs/mixins.js I get the following error message:
Unable to resolve the source file for 'frontend/theme/name/de_DE/mage/requirejs/mixins.js'
<pre> #1 Magento\Framework\App\StaticResource->launch() called at [vendor/magento/framework/App/Bootstrap.php:263]
#2 Magento\Framework\App\Bootstrap->run(&Magento\Framework\App\StaticResource#0000000069ad91c00000000031b30d8d#) called at [pub/static.php:13]