Default template has no generator attribution
From the API doc pages that gi-docgen outputs, it's very hard for an uninitiated user to determine what program generated them (i.e., to learn that gi-docgen exists and was used). There doesn't seem to be any mention of gi-docgen in the default template--neither in searchable text nor HTML source. This impedes the path from a user seeing something wrong with generated documentation (such as a layout issue or incorrectly-generated docs) to fixing it--they have no starting point to even find out what software generated the page they're looking at.
It would fix this to mention gi-docgen in the generated documentation, perhaps at the bottom of pages. Including version information would be good too, for tracking down issues/improvements between versions of the doc generator.
For comparison, gtk-doc seems to say "Generated by GTK-Doc V1.33.1" or similar.