Why addons_contrib script does not register?

I downloaded object booleans script from github but I found that is already shipping with Blender.
Blender\2.68\scripts\addons_contrib\object_booleans.py

However it seems that it does not work and can’t be registered. Neither does show up in Addons menu in preferences. Do you know what is going wrong?

It’s a testing category addon. Enable that category and you should see it.

Oh, now I understood it!
http://wiki.blender.org/index.php/User:Ideasman42/ProposalAddonsContrib