It often shrinks files much smaller than standard ZIP formats using the LZMA algorithm.

While "05sg.7z" isn't a widely recognized software or public dataset, it follows the format of a compressed archive created with 7-Zip . The ".7z" extension indicates it uses the 7z format, known for its high compression ratios and security features.

Here is a blog post draft tailored to explaining what this file is and how to handle it. Unlocking 05sg.7z: A Guide to Handling 7z Archives

The format is a compressed archive format similar to ZIP or RAR. It was developed by Igor Pavlov and is the native format for the open-source 7-Zip software.