I don't recall seeing this mentioned here, and since I just
spent all morning discovering it, I thought I'd let people
know.
The default crypto policy changed once again in fedora 33,
which I didn't notice till I started trying to use rsync to
update my web pages on hostgator (which, by default, uses rsa
keys).
Kept asking for my password even though I had the keys loaded
into the agent. Very mysterious till I finally started poking
around on the internet and found this:
https://dev.to/bowmanjd/upgrade-ssh-client-keys-and-remote-servers-after-...
Adding a line to in ~/.ssh/config worked:
Host
tomhorsley.com
Port 2222
PubkeyAcceptedKeyTypes +ssh-rsa
Maybe I'll try to discover if hostgator accepts more modern
keys and add them (later).