Certified user identities in keys can be revoked using the same popup
for certification.
Requires GnuPG 2.2.24 (not available in distro's repository, not fully
tested to date).
The email parameter must have a valid email address format here, else
GPGME will refuse to create the identity. This is not the case when
creating a key, where any string is accepted.
Correct format :
name <email> (comment)
Was :
name <email> comment
Though the 'comment' part was visible with the cli gpg app, it was not
shown in kleopatra and in K7.
Result : fails.
Reason : loopback passphrase provider is never called.
With default pinentry mode, the passphrase is requested normally
and the private key is exported. But this can't be done on a web server.
Enclosed in #ifdef DEVTIME.
In-place editing with a popup if user is allowed in app config file.
User must of course manage at least a private key. User identities of
target key may be selectively chosen. Optionally, certification may be
exportable and non-revocable.