We already detect mail addresses for different purposes and thus it will be easy to enclose them in angle brackets just for comparision.. Almost all trust signatures out there are created by gpg and used to restrict the mail domain. No need for different regexp. See also the comments in the code related to the history.

Fixed Gpg4win version: https://lists.wald.intevation.org/pipermail/gpg4win-announce/2022/000098.html

As usual see https://gnupg.org/download for links to the latest packages. For Gpg4win see https://gpg4win.org

$ ping git.gnupg.org
PING git.gnupg.org (217.69.76.56) 56(84) bytes of data.
64 bytes from cvs.gnupg.org (217.69.76.56): icmp_seq=1 ttl=58 time=6.74 ms
64 bytes from cvs.gnupg.org (217.69.76.56): icmp_seq=2 ttl=58 time=6.87 ms

You need to assign a drive letter.

My suggestion is to clearly state that there is a direct Key Signature with an expiration date. Another feature would be to add a separate command to modify Direct Key Signatures. However, the latter has the problem that it help with proliferation of such signatures and other OpenPGP implementation will run into other problems. Thus for the whole ecosystem such an option is might not be a good idea.

Direct key signatures are rarely used. IIRC, we implemented that the same way PGP did it.