I was reading some source code to be more familiar with the API but I couldn’t find what “co” property means in this:
I searched the online scripting reference but I couldn’t find it.
Anyone can please help?
It stands for the location of the COordinate. One of the less intuitive names in the API.
Thanks Atom for clearing this up 
It’s here, but the explanation isn’t very helpful yet, no mention of coordinates.
Thanks Sanne for digging that out. It would be useful if they said what it was rather than the type which is easy to figure out :yes:
I think it’s just not complete yet. AFAIK there’s only one main developer for the Python API, and he did a great job so far, but while he’s very active and commits several times a day to the Blender codebase (it’s Campbell), he also has other responsibilities, like preparing bmesh for inclusion in trunk and general bugfixing.
But, as you did, people can always ask the community for help if they get stuck. 
You are right. I agree the scripting API is kick ass. The blender community seems pretty helpful like you said so no problem