Thanks for elaborating and the reference to rfc2440 - I now understand where that stray mail (between [RFC2822] and name-addr) in rfc4880 comes from...
Anyway, I'll treat it as if it says RFC 2822 mailbox and will treat angle brackets with bare addresses as optional.

I see, I had rfc2440 in mind which says:

By convention, it includes  an RFC 822 mail name, but there are no restrictions on its content.

thus 4880 refined it a bit. But in practice it is not the same because it is utf8 and not punycode or whatever. let's close this bug because they way it is used will work with all mail clients.

Thank you @werner ! I can confirm that the patches that have landed on STABLE-BRANCH-2-4 do clear up the DoS i was seeing for signature verification.

Also fixed for 2.4

This has been fixed in master with rG48978ccb4e:

Well, the different outcome depends on the order of the certificates or the string comparision in keyboxd. So it is not a keyboxd vs. pubring.kbx thing.

Closing this as duplicate of T7405. That ticket has the better task description as it was made after discussing offline how it could best be done.

For master fixed with rGbb6b38c24010258c7cb2da840d0a088fe43393b3 (Wrong bug id used).
Also fixed for gnupg24.

Pushed the fix for exporting OpenPGP v5 key: rG57dce1ee62c2: common,gpg,scd,sm: Fix for Curve25519 OID supporting new and old.

The OID is used for fingerprint computation, which complicates things.

Using the shorter OID for v5 is on purpose; thus we need to fix the export.

See new subtask T7290 for smartcards and the link entries mentioned above.

FWIW: the encryption part of the ADSK feature has been released with