Uh, this is quite verbose :-/

"The following information [a boolean, not the event details] is sent when the specified event occurs: - Sign-in Error - Account creation - Login succeeded - reset password - updated password - Joined a channel - Created, edited or deleted a message - searched for a term" … and the list goes on: https://docs.mattermost.com/administration/telemetry.html

Thanks for letting us know…