I can’t click that link. I guess Droid-ify doesn’t handle that protocol. If I try to paste the entire thing into the address field of the “Add repo” screen, it crashes the whole app. Merely pasting it!

I had to separate the bits and do it manually:

Address

http://fdroid.ironfoxoss.org/fdroid/repo

Fingerprint

C5E291B5A571F9C8CD9A9799C2C94E02EC9703948893F2CA756D67B94204F904

Hopefully FFUpdater will add the app to their list soon. And Droidify will probably add the repo to their default list, too.