Google calendar messages (meeting invites and updates, not meeting reminders) have the header
Alas, filtering by
mailed-by:calendar-server.bounces.google.com does not work.
How can I filter the Google Calendar messages?
At this time I am using
subject:("Invitation:" OR "Canceled Event:" OR "Declined:" OR "Accepted:")
but this does not include meeting updates because their subject sometimes starts with
[Update] and Gmail filters cannot handle brackets (even with backslashes &c - believe me, I know regexps).