[pxoe]

Yeah, I wanted to add that it may be less of a problem when there's source code, but sideloading and third party app stores includes apps that don't have source code available, like random loose apks people just download and install, or just third party stores that aren't open source oriented (like game stores, phone maker stores, etc.) Checking source code is also not an option on play store itself, so they might want to have some other ways of verifying where something comes from and letting other people check something for themselves.