Microsoft repository installed on all raspberry pies, you can switch to other OS other than Raspberry OS (previously Raspbian) or you can take other steps to remove it. Make sure somehow to notify Raspberry OS devs that this is not ok. More on this reddit post (from teddit mirror):
This is crazy.
@m_svo What bothers me most is that they did that silently. Maybe someone has need for Microsoft products on RPi but they had to notify users of optional repo to be added.