As far as I'm aware, the knowdb bit in MBases means that the NPC will 'sell' you that specific information (for example, where a jumphole is)
Hope that helps

Thats not really what I meant.

"know" and "knowdb" are the entries to make NPC's sell you information about specific objects. Besides, knowdb is redundant.

But rumorknowdb is linked to a rumor and, as the name says, has something to fo with rumors.

Look it up yourselves...

I know this is a really old one, but i'd really like to know about this, so does someone know what these entries do?

I'd test it myself, but I don't have the time at the moment, and if someone already knows about this, that would be neat.

The info for these, are in the Data\Interface\KnowledgeMap.ini:
(Search using the second number.)
IIRC, the numbers are:
(Object Data, Item Name, Range around object to reveal, Treat it as "Visited."
know = 251650, 253609, 3000, 1

This, IIRC, will reveal ONLY that object, on your map:
knowdb = br01_01

BOTH entries are required, in order to have the object revealed to you.

IIRC, the following will provide information, but won't reveal it on your map:
rumorknowdb = li01_13

I messed with this once, while writing one of the "Privateer: The Reckoning" mods, but you've got to add entries in KnowledMap.ini, have a DLL, and some other place, which I can't remember right now.
It never made it into any of the mods, because the number of entries became astronomical when I created the Gemini sector.
Well, that, and the fact that there were so many bugs, that I never got around to finishing this section of the mod.

Watch your 6!