I'm sorry for the confusion:
My extension had a non-standard folder structure (but it worked nonetheless).
I built it with the extension developer extension which does a good job in making extension development more comfortable.
Unfortunately, these builds weren't recognized by the WTS-System used here.
So I uploaded a version which would recognize the language files, but this version didn't work as extension.
To end the confusion:
- I'm using now my own simple UNIX bash script for extension packaging.
- The folder structure is now following the standards.
I released a new version (0.6.4, no new strings to translate) including the translation from menet and Cashman and uploaded it here as well.
It works with the WTS and is the same working extension that I provide for download on https://blueimp.net/mozilla/
So thanks to both of you for the translation effort.
Thanks especially to menet for pointing me here.
And thanks to MatrixIsAllOver for the welcome.
@Cashman: I sent you a PM before, but it doesn't show up in my box of sent PM's, so perhaps it didn't reach you.