If I search for `messageclass:meeting` in my emails with Outlook on the web, what kind of search is it doing?

Question

On How can I only list emails that contain meeting invites with Outlook on the web?, one suggestion was to search for messageclass:meeting in my emails with Outlook on the web. It does return some emails, but not necessarily meetings: it seems to return some emails based on the text the email contains.

However, what kind of search is it doing? Is it simply some string match and it, which string(s) is it matching (e.g., must an email contain messageclass and meeting?)? I couldn't finder a pattern yet.

Answer 1

From my understanding, messageclass:meeting is broken down into 3 strings: message, class and meeting. An email must satisfy these 3 conditions:

• have 1 word that has message exactly or as a substring (e.g., "message"),
• have 1 word that has class exactly or as a substring (e.g., "classifier"),
• have 1 word that has meeting exactly or as a substring (e.g., "meetings").

Similarly, researchtalk:meeting is broken down into 3 strings: research, talk and meeting.

However, researchtalk is not broken down into 2 strings: an email must contain the word "researchtalk" or have a word for which "researchtalk" is a substring. Same for messageclass.