The .7z format is an open-architecture container with several advanced features:

: Can group multiple files into a single stream to achieve a higher compression ratio for similar data types. How to Open or Extract PICT0042.7z

To access the files within this archive, you can use several free and open-source tools:

: Likely uses LZMA or LZMA2 algorithms, which provide high compression ratios compared to standard ZIP files. Technical Characteristics of the 7z Format