You can use 7-Zip on any computer, including a computer in a commercial organization. You don't need to register or pay for 7-Zip. How to Extract .7z.001 files - Microsoft Q&A
The file is the first segment of a multi-part compressed archive created with 7-Zip . This format is typically used to split very large files into smaller, more manageable pieces for easier sharing or storage. Technical Breakdown Format : 7z (Lempel-Ziv-Markov chain algorithm).
: 7-Zip is the native and free utility for this format. macOS : Use The Unarchiver or Keka .