civ3 mod has cities restricted to certain tiletypes, where is this defined?

[thistleknot]

I've tried looking into tileimprovements and constants, and did a search for city as well as plains in the gamedata folder...

no luck

help please

[thistleknot]

found it

at first I thought it was in orders.txt when I saw "Unit_Pretest_CanSettle"

but I saw another entry for settle in my search, units.txt

and in there, I saw settle: land
settle: mountain

I'm not entirely sure if that's all the civ3 mod does...