I downloaded some missions and would like to know where/what file contains graphics settings? I noticed some missions allow users to play online with their own video setup and some 'force' terrain detail to a specific setting.
"some missions" is really generic. It's surely in one of the sqs/sqf files...
on a more serious note, the script should be named is such a way that you would be able to find it (if the mission designer had done it in an organized way).
Without knowing witch mission you are talking about, and the link to it, don't expect someone to be able to tell you where to find it