Even you can improve the manual by describing the feature of each Action Type
A nice request would be to have an Icon on the right top of the Action Type for example "?"
When clicking to that Icon it will show the corresponding script in the Script folder of AC
In that case we can open Monodevelop or VS to better understand the functionnality of that script
Comments
You can also see descriptions for each Action within the Actions Manager - just click on the name, and you'll be given more information.