Hello,
RSCALE=CHINESE
RSCALE=ETHIOPIC
RSCALE=HEBREW
RSCALE=GREGORIAN
…
These are part of RFC 7529 (iCalendar Extensions for Non‑Gregorian Recurrence Rules), perhaps not supported inside iCalendar?
RFC7529.zip (1.7…...Gregorian event instances or RDATE values. Similarly, VAVAILABILITY and...will have limited practical value. If you can provide specific...