More than likely it was a project that only builds in a long-discontinued non-conforming C/C++ compiler that only runs on Windows 95. When I was working at MS very recently I was surprised to learn that all software affected by the Sun lawsuit, way back in 2001, was still strictly verboten, even internally. All builds of Windows 95 through XP SP1 were absent from the internal builds and products shares just as they are from MSDN. I don't believe Microsoft would have somehow lost this source code as the article speculates - more likely they reasoned that the effort needed to get a build environment set-up and working would take more time than finding someone on the team who really knows x86 assembly well enough to manually fix the bug - and there are plenty of people like that on campus.