Windows Chicago build 73f was leaked on BetaArchive by member sunnyblueman. It is nearly identical to the previously leaked build 73g. However, this is an internal Microsoft build, and thus was not released outside Microsoft. The only difference between the two is that 73f features an internal version of the WinBug tool, while 73g has WinBug for external testers. It is safe to assume earlier compiles of this build (73a to 73e) also exist.