SSH-Keygen Fingerprint and SSH giving fingerprints with lots of letters and numbers
Turns out that SSH recently switched from using MD5 fingerprints (what I refer to as a "traditional" fingerprint) and now uses SHA256 fingerprints (what I referred to as gobbledygook).

I'm guessing that with El Capitan OS X is now using a newer version of SSH that is using the new SHA256 default.

For those of you who find this, although SSH will give you an SHA256 fingerprint by default, you can ask SSH to give you an MD5 Fingerprint.

ssh -o FingerprintHash=md5 [server]


It appears that on my Mac, that the command

ssh-keygen -lf /path/to/key


now defaults to an SHA 256 fingerprint. However, if you're using Ubuntu, it looks like ssh-keygen is still defaulting to MD5 (maybe I need to update my ssh package on Ubuntu).

Here is the post that I finally found once I started using the right terminology:
https://superuser.com/questions/929566/sha256-ssh-fingerprint-given-by-the-client-but-only-md5-fingerprint-known-for-se