There's no documentation, but you can see the widgets on your page and use JustDecompile to view their templates (if they aren't available in the backend already)
I think search and navigation are the likely two...I can't think of another that uses it off the top of my head.
- Anyway, download the (free) JustDecompile
- Search for the offending widget
- In the code it'll tell you the location of where it's template is located, then you can just go browse the DLLs for it, extract, change