The wiki at wiki.gnupg.org has some documentation, that can be moved here. The main contributor @bernhard has given his ok. Invite the community and, assuming broad consensus, convert documentation and import it here for further editing.
wiki.gnupg.org is written in moinmoin and creole markup.
As the wiki.gnupg.org authentication was relying on bugs.gnupg.org, which is shut down, this task has a high priority.