: If you don't see the file, ensure you are looking in the root of the GTA V installation folder, not inside the update folder.
: Once your new "feature" (modified file) is ready, use OpenIV to "Replace" the original file inside the archive with your new version. Potential "Features" to Add Depending on your goal, adding a feature usually involves: X64u.rpf
: Adding or swapping vehicles, weapons, or character models (.yft, .ytd). : If you don't see the file, ensure