Can anybody identify this?

[xylophone]

Fell out of my laptop when I was repairing it. Seems like a cushion, but dont know where it goes

 

[krspkbl]

What repair were you doing? Nothing should fall out (ideally lol). The first thing that came to my head is maybe a broken key hinge but if you describe it as a cushion I assume it's soft and not a piece of plastic?

I've had some keys jam on previous macbooks and with a shake or removal of a key a piece of plastic from the key hinge fell out. Nothing yet on my M3 air.