You can just leave it blank or write 60 day covid extension. One of the extra forms you fill out for the covid extension asks for the reason. On that form I ticked the second box 'embassy not issuing visa extension letters' (can't remember the exact wording)
Registering me to a hotel they operate instead. I'm unsure what to do, I've already booked and prepaid for the airbnb, but don't want to break any rules.