I don’t have the answer. But I’m immediately reminded of the Yugo or Trabant or any number of British made cars. Loose parts floating about. lol
It looks almost like a support part that would have been attached to the case as part of manufacuring when it was first stamped out of the parent metal and when it was coated and baked and ready to ship it was broken off, and instead of being removed it fell inside?
have you reached out to framework support on this? they dont monitor the community forum so if you want positive confirmation you’ll have to reach out to their support team.
Either way, it doesnt’ look structual or important, so as long as it didnt’ short something out or anything it’s probably fine now that you’ve removed it. 
This looks to be a mounting bracket of sorts. Definitely holes for locating, and slotting onto fixed screws.