I've found this: https://docs.microsoft.com/en-us/microsoftteams/limits-specifications-teams#class-teams which addresses a couple of important limits. While that's helpful, we have been getting questions from faculty on what appear to be a limit of file attachments per submission and also on the length of the feedback they can provide. I can't find any specific documentation on those details. All in all, the lack of documentation around Assignments is quite disappointing. In general, we are a Blackboard Learn school, but have a small number of vocal faculty who insist on using Teams (against our advice) for their classes and then complain about arbitrary limits (which, ironically, don't exist in Bb Learn).