Use a tool like 7-Zip or WinRAR to extract "part1.rar"; it will automatically pull data from part 4 and other segments.
These files are usually moved to the game's internal DLC folder or a "custom_songs" folder created by the community. FUSER.ALL.DLC.part4.rar
Based on community guides for these specific delisted archives: Use a tool like 7-Zip or WinRAR to extract "part1
These archives typically aim to complete the setlist, which originally featured: which originally featured: