Open the file in a hex editor (like HxD or Ghex ). Ensure the header starts with the standard 7z signature: 37 7A BC AF 27 1C 00 03
The first step is to verify the file type and check for "low-hanging fruit" like embedded strings. gt00.7z
Running file gt00.7z confirms it is a 7-zip archive data. Open the file in a hex editor (like HxD or Ghex )