If (and only if) the .git is for a module supported by Kotor Tool's module editor, you would need to first extract the RIMs for the module (right click on the RIM to see extraction menu) into a project folder, then replace the .git there with your custom one.
You also need to copy in any items (ut* files) that are directly referenced by the .git into the project folder, and any that are indirectly referenced (via scripts, encounters, etc.) into the "extras" folder below that.
P.S. I split this post from the other thread because it is a good question all on its own, it really serves users better this way (IMHO), and hijacking a thread with a not-exactly-relevant question is not nice.
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