To help clarify to GP (was going to help reply then saw yours) F-Droid is both the name of the core website hosting the APK repos and build infra, and the name

To help clarify to GP (was going to help reply then saw yours) F-Droid is both the name of the core website hosting the APK repos and build infra, and the name of the Android client which can connect to any F-Droid compatible repo - there are a bunch of projects who host their APKs in their own F-Droid repo, all you have to do is go to their website and scan the QR code to add it or enter manually. Signal could run their own F-Droid repo and people just add to their F-Droid client without using or touching the F-Droid website or build infrastructure at all, which would allow folks to do as lucgommans explains - one phone client connected to many repos, no manual downloading. Example: https://www.bromite.org/fdroid https://www.bromite.org/fdroid