A "Split 7-Zip Archive" (part 6). These files are created when a large collection of data is broken into smaller chunks for easier distribution or storage.
If part 006 is missing or corrupted, the entire archive usually cannot be extracted. GAm.7z.006
Based on the "GAm" naming convention and common internet archive practices, such files often contain emulation ROMs or large game collections. How to Review the Contents How To Extract Games Using 7zip A "Split 7-Zip Archive" (part 6)