[Modding} What is exposed

So yea, maybe this is slated for the modding patch, but figured I would ask anyway.

Going through the xml an especially the RaceTraitDefs and AbilityDefs.xml I can see a whole lot of things that are available but creating new and unique abilities i do not know nor do I see any documentation to what is exposed to the xml to use as actions and if they use valueparams , events and such to create new abilities. 

Is it supposed to be just those used so that I really can not create new abilities but only derivatives of what is there.

If not when is this information going to be released or am I missing something where this is defined.

(hope this makes sense)