You can extract any Debian package (.deb) using 7-zip and repack the data as 7-zip archive (.7z, .7-zip, .7-z, .s7z etc.). However this procedure will make the resulting file not recognizable in Linux for the purpose of installation package.
Convert Debian Linux package to 7-ZIP compressed 7z archive file.
We found 3 software records in the database related to .deb to .7z file format conversion.
Microsoft Windows software - convert deb to 7z on Windows
Popular open source file archiver with a high compression ratio
Convert from deb file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned deb to 7z. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A free open source archive utility
Apple macOS / Mac OS X software - convert deb to 7z on OS X
Full-featured compressed archives manager