If you have all 60 parts sitting on an old hard drive, extracting them will unlock a snapshot of arcade emulation as it existed in 2011. If you’re just learning about it, take this knowledge as a lesson: always check for Part 1 first, and keep the past alive—one .rar volume at a time.
When you see a file labeled part48.rar , it indicates that the total collection—which likely contains thousands of arcade games (ROMs)—was so large that it had to be split into smaller chunks for easier uploading and downloading. MAME-Plus-v0.139u1.part48.rar