I want to make an inbox rule in Outlook on the web to categorize meeting invites/updates/cancellations, but can't find the search or rule syntax.
The Microsoft rules documentation doesn't have any details about specific filter criteria.
I found this answer about item type searches but it doesn't work in OWA. Searching messageclass:IPM.Note or [Message Class]:IPM.Note just finds emails with text "IPM".
This answer using the rules wizard uses a specific macOS GUI option that OWA doesn't have.
This university helppage uses an email header search X-MS-Exchange-Inbox-Rules-Loop: ePanther@uwm.edu which led me to a possible solution: creating an email rule with the header search X-MS-Exchange-Calendar, which in my inbox I observe all invites having. It seems to work... but it also seems hacky.
Searching for message body text inviting you to a scheduled Zoom meeting has a pretty good hit rate as our company uses Zoom exclusively, but your mileage may vary. (This has the added effect of surfacing invitations that have been forwarded as plain emails.)