Okay, thanks @j-ed!
Adding authenticationless calendars not possible?
Some calendars need no authentication like Firefox releases - I did not find a way to add it, “next” button is deactivated when no username/password is entered. Maybe add a checkbox “no authentication needed”?
DAVDroid 0.6.8 from f-droid on CM10.0@SE Satsuma here.
Actually it is not a WebDAV service.
You just type a .ics uri, and it is not DAVdroid intended for.
There are quite a few apps that can sync ICS-files with local calendars, but none of them seems to work properly with timezones. I tried a few of them and always got one or two hours offset from a perfectly normal ICS file.
Nowadays I use my own program to sync the ICS-content to a CalDAV server.
Oh yeah. I completely missed that. Sorry for bothering and thanks for the help!