Christian was kind enough to explain on #gentoo-infra that the gpg public key information required in the SecureMail[1] tab should be obtained by running: gpg --export --armor $user@gentoo.org Please add this information to that page so others can benefit from it too. [1] - https://bugs.gentoo.org/userprefs.cgi?tab=securemail
In some cases that will lead to a fairly large key. # gpg --export-options export-minimal,no-export-attributes --armour --export $EMAIL Will give you a much more usable fragment.