It has been noted that there are some quite important privacy leak in the
OpenPGP "Version:" and "Comment:" that contain usually very sensitive
information regarding the software version used.
In the NSA XKEYSCORE's ages, those kind of information does provide a very
important weakness.
The Adversary capable of massively monitoring communications, profiling who
encrypt their email communications, can profile the exact version of encryption
software used waiting for a vulnerability to be found.
When a vulnerability is found for the exact version of the encryption software
used, the adversary can exploit the "exposure window" by having a prior
knowledge of the end-point encryption software weakness.
This ticket is to improve GnuPG not to permit, by default, to insert any kind of
"Version:" and "Comment:" headers, unless the end-user explicitly require to do
so with a command line argument or a configuration line.