It supports several compression schemes:
- LZMA (the default for 7-Zip prior to 9.30 alpha)
- LZMA2 (the default for 7-Zip 9.30 alpha +)
7z files begin with signature bytes
'7' 'z' BC AF 27 1C.
The 7-Zip software will automatically find embedded 7z data in many cases (but apparently not if the file extension is .7z). This makes it possible to create hybrid files that look like some other format, but which will be interpreted as 7z format by 7-Zip.
- Refer to the DOC/7zFormat.txt file in the source distribution