The text should be translated to german in the default.po file

Ah, one more question: There is a difference between msgid "" "Export your own shifts. and sprintf(_('Export of shown shifts.. Probably introduced by rebasing my local branch onto upstream/master. What is the reason for the duplication of the displayed text here? Is another commit needed, to align both strings?

Hey Katrin, nice idea. Would you like to write a manual for engelsystem.de / https://github.com/engelsystem/engelsystem.de to link as user documentation? I don't want links to other software in the engelsystem itself. Please let me know.

don't want links to other software

That's not really a motivation for me to start writing documentation about a problem, because it isn't merged into exactly that GUI element it IMHO fits best ;-) I can remove the DAVDroid snippet if you want, but I think this PR would become less useful then.

Imho it's a good decision to keep the Engelsystem free of links to other products as they need to be maintained / updated / removed if the linked products change or there is a better suitable one.
In a documentation that's another point, there would be enough room for a list of potential clients on all other platforms like Apple devices and laptops.

How is maintaining hyperlinks (or letting volunteers to do so) within the system different from in the docu?

The documentation gets deployed to [something].engelsystem.de so its under the control of the maintainers and can be updated. In contrast to the Engelsystem which gets released once and then stays at that version with potential outdated / wrong links?

I put the links to the doc and added a help button to the engelsystem wich opens the doc at this point.

Thank you :-)