gnus-user-agent

gnus-user-agent is a variable defined in `gnus.el'.
Its value is

(emacs gnus type)

Documentation:
Which information should be exposed in the User-Agent header.

Can be a list of symbols or a string. Valid symbols are `gnus'
(show Gnus version) and `emacs' (show Emacs version). In
addition to the Emacs version, you can add `codename' (show
(S)XEmacs codename) or either `config' (show system
configuration) or `type' (show system type). If you set it to
a string, be sure to use a valid format, see RFC 2616.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.