I’d like to mod a map that I forged, but in order to mod my map, my map needs to be a .map file, which is supposed to be the default file type. MCC is saving my Halo 3 maps as .mvar files instead, which is the file type used for built-in maps made by Bungie. This is not typical. Maps that have been forged should be, by default, the .map file type. Also, FYI, I’m using steam. This fix is really important to me, so if you yourself don’t know of a fix for this, think of someone you can share this with who might. TL;DR I need to get MCC to save my Halo 3 maps as .map files but instead it’s saving them as .mvar.
Maps and MVARs are separate things. A .map is the actual base map's cache file. These are files which contain all of the tag data for the scenario and the included objects. These are large files. For example, Foundry has a single .map file (called warehouse). A .mvar is a map variant. MVARs are small files which contain data about the placement and position of objects on a map. For example, MLG Onslaught is an MVAR built on Foundry. A map variant you save in forge is an MVAR, not a map. I imagine your modding will involve poking tags within the .map file. Note that, depending on what changes you make, this may make map variants incompatible with it.