To clarify Obtainium is used to get and update apps from github/gitlab/forgejo/dev website directly and somewhat comfortably. Instead of using f-droid as an appstore. Why you might want to do that is eg explained in this video: https://www.youtube.com/watch?v=IAoCfrqxIEg Personally(!) idgaf and just use f-droid. This is no security advice because am dumb.