You don't strike me as the kind of person that would litigate such things, but I would like to think that if the right people at Microsoft became aware of such a liability, they might choose to give you credit (to be on the safe side).
Apache 2.0 by the looks of things.
Interesting question would be whether WinGet is a "derivative work" of AppGet.
They don't share any code. As far as copyright law is concerned, it is not a derivative work.