Time Zone value for CalDav calendar

Rainlendar2 Bug Reports
#1

Rainlendar seems to store time zone info with a prefix which is not really compliant with other clients.
The added prefix is confusing for e.g. Nextcloud, Thunderbird and they fall back to local time with some drawbacks

TZID:/freeassociation.sourceforge.net/Europe/Berlin
DTSTART;TZID=/freeassociation.sourceforge.net/Europe/Berlin:
20230913T130000

should simply be:

TZID:Europe/Berlin
DTSTART;TZID=Europe/Berlin:20230913T130000

Also there is a CRLF created between TZID and timestamp

I think the prefix is coming directly from libical an maybe should be “reset” via

icaltimezone_set_tzid_prefix("");

#2

The library seems to force the prefix so clearing it will just add it back again. The iCalendar standard doesn’t define what the TZID should be so I don’t think calendar apps should try use it for anything else than to match the event dates with the provided VTIMEZONE.

Anyway, I can try to change the libical so that if doesn’t add the prefix and see if that causes any problems with the timezone handling.