gnome-help-browser had an ability to render all of the documentation formats well. It is superseded by yelp, which is much better at DocBook and custom-XML-doc

gnome-help-browser had an ability to render all of the documentation formats well. It is superseded by yelp, which is much better at DocBook and custom-XML-documentation-built-for-GNOME schema (edit: Mallard), but you can still do "yelp man:ls" or "yelp info:find" to get man pages or GNU texinfo pages rendered directly with it. Documentation is catalogued by ScrollKeeper. Indexing is the missing bit, I guess, and a more of a "directory view" into all available documentation. I think it is more realistic to accept the nature of different tools and see what we can do to make it more manageable for consumption (browsing, reading, searching and discovery). But it's such a non-glorious problem that nobody will bother with it.