On your phone, with F-Droid or Droid-ify installed, tap:
Or scan this code with the app (F-Droid: Settings, Repositories, +; Droid-ify: Repositories, +):

Or enter the address by hand:https://beta.murmel.blue/fdroid/repo?fingerprint=897732C70A7DD2529259BCF0386168AD8AC1DBBCF48A724E2E9702910B0FE2A0
The app checks the fingerprint; if it shows a different one, do not add the repository.
Privacy: downloads come from a privately run server. Your IP address is seen by that server while you download; its access logs keep only a shortened address for a few days.