gtk-doc
Just released gtk-doc 1.20 with lots of bugfixes and feature request implemented (32 tickets closed). If you are a developer, fetch it and rebuild your docs - I hope you like the new look!
The biggest feature is the large improvement over the rudimentary markdown support gtk-doc had - thanks to William Jon McCann for the contributions. Take a look at the manual to learn about the new syntax. We chose markdown, so that the syntax looks good in the sources and you can already go ahead using it. If someone builds with an older gtk-doc things might show up as is, but thats not the end of the world.