Product Owner and Scrum Master role during standup
Should a Product Owner and Scrum Master communicate what they have done yesterday, are doing today and their impediments in the standup like the developers?
My view is that the standup should be observation only for the P.O and the S.M. can raise observations at the end, otherwise they are just there to facilitate as they are not directly working towards the sprint goal.
The daily scrum's purpose is to coordinate the team. If the PO or SM had tasks that were required for the team to coordinate then yes, they definitely need to speak up so the team can do so. For example maybe the PO or SM removed an impediment. That is important to know.
If not, then their input is not required and they should assume their regular roles, the SM as a facilitator and the PO as a (preferably silent) observer.