Where does Search search?

I created a new topic here because I didn’t get an answer there:
http://modxcms.com/forums/index.php/topic,6671.msg48326.html#msg48326
So I put it here again: The "Flexsearch" (or whatever snippet you use) how and where does it search? How does the search works at all? Is it part of the core? Yeees: I could try to figure that out for my own, but why - in the MODx forum, where all the experts are around

It searches from site_content table; from pagetitle, description and content fields. No tv’s, snippet outputs or plugins etc.. But there has been talk to create a search index in modx in future versions to develope the seach further, eg. search from all content.. ofcourse, with clever sql queries, it would be possible to search from tv’s allready, but doing it straight with sql is not very efficient. There is improvements on the way, don’t worry, be happy!

I’d have to look at it, but I am pretty sure xyzvisual (Javier) did modify FlexSearchForm to include TV in search...

Edit: Found it : FlexSearchFormTVars

You also could look into HyperFlexSearchForm

I wished we had a new FlexSearchForm snippet pulling all this togther, for better search... at some point we had talked about some Sphider integration also, which would be great...