Last year, I discovered that the Kosinski compression format is actually LZEXE, which was used for compressing DOS executables back in the 90s and the late 80s. Its developer catalogues three versions on his website: v0.90, v0.91, and v0.91e. While only binaries of v0.91 and v0.91e can be found on the website, v0.90 can be found mirrored on various other websites.I got in touch with LZEXE’s developer, Fabrice Bellard, and he was able to release LZEXE’s source code, untouched since 1990! It is re...