Forum OpenACS Development: Where can I find basic OpenFTS developer information?

I've searched the forums and I've found a fair amount of installation documentation, and some people are clearly using OpenFTS, but there doesn't seem to be any documentation on how to integrate a new package into the search index.  Nothing in the OpenFTS driver package.  Is there anything I can look at before I start mucking through "notes" to figure out how it was done?  A description of the API?  (This is for the package tutorial I'm working on.)