Facebook sent me what might be the last PGP-encrypted email they will send me yesterday: "Encrypted notification emails are going away soon
Hi Jim,
Encrypted notification emails are going away on December 5. This means that, soon, emails you receive from Facebook will no longer be encrypted.
If you have previously set up a public key, you can still view it under settings on Facebook (or in the Accounts Center under Password and security) until December 5.
Thanks,
The Facebook Security team"
Sad. It was another layer of defense against password reset attacks -- the confirmation code was sent encrypted. (Though I don't know why it doesn't just insist on me using my registered security keys for confirming a reset instead of creating a loophole for security key bypass.)