Broken Themes – Notes folder location?

In my themes folder I get a error

Broken Themes

The following themes are installed but incomplete. Themes must have a stylesheet and a template.
Name Description
_notes Stylesheet is missing.

I build a theme based on 2010 and using a security suggestion from “digging into wordpress” guide I have a subdirectory to “mask” the location of the main files for the site.

First question is where does the _notes folder go, Second is what is it for. And third what is my best approach for reinstalling the theme or do I want to completely reinstall the site.