FIDO U2F keys are being phased out in 2025 - make sure to replace those in time

Can somebody PLEASE put that announcement into layman’s english and tell us how we can determine if we do (or do not) need to do something ?

I have no $#%#$% idea what a FIDO U2F key even is let alone what the setup instructions are trying to tell us to do.

FWIW - I’m a premium user setup currently with an authenticator app and multiple yubikey 4 and 5NFC physical keys. No passkeys. I get prompted to insert a yubikey and press the button on it. Simple. Do I have to do anything at all ?