BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Test//Test//EN
BEGIN:VEVENT
UID:event@example.com
DTSTART;TZID=Europe/Berlin:20250115T100000
SUMMARY:Event with forward TZ ref
END:VEVENT
BEGIN:VTIMEZONE
TZID:Europe/Berlin
BEGIN:STANDARD
DTSTART:19701025T030000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
END:STANDARD
END:VTIMEZONE
END:VCALENDAR