Dang these are much more useful than my first port of call for looking up http codes... which is http.cat/<code>. It's a shame you have to know what a code is to get to it... e.g. /404-not-found works instead of /404
I still haven't reckoned the security implications, but Bitwarden supports passkeys, you can mostly use them the same way as you do a username/password across devices.