Put a pgp signature in a pdf file
Allow putting a pgp signature in a pdf file. This is not fully documented inside the specification, but basically it is replacing the CMS bundle as described with a pgp bundle.
These signatures are tagged in the g10c namespace (https://github.com/adobe/pdf-names-list/issues/45) and is only implemented in the GPGME backend as a 'whatever gpg understands'.
A special difference is that the signature is not padded with zeroes, but with a gpg comment packet with the exact size to fill the void.