BeOS versions of many useful utilities. UnRAR, UnARJ, Cabextract, CHMTools etc. Original sources from various authors under various licenses. The sourcecode is available during installing of those BeOS packages.
Utilities developed for Haiku but not accepted to upstream (VHDTool, rtic) are also published here.
You can find here source of some hobby tools, like ATS909Hog.
This project is an attempt to create a wrapper between filesystem code for one operating system and compile it for another. For example, a Linux filesystem driver could work natively in Windows if the project goes as planned.