
Apple appears to have pulled the publicly accessible Mac OS 10.4.8 Source Code (Darwin, the open-source foundation of OS X, and XNU, Darwin's open-source kernel), leaving only developers with ADC log-ins with access to the code (public link, ADC link)
Earlier this week, the OSx86 project released a version of the 10.4.8 kernel that was hailed to be 100% legal according to the APSL and run on any x86 machine. Prior to this release, Apple's code would only run on Apple's hardware due to various dependencies (such as EFI).
While the code could run under single-user mode on any x86 machine, it would not boot up into Apple's familiar OS X Aqua interface without Apple's TPM (trusted platform module) keys which are illegal to distribute (but are reportedly floating around the internet).
The circumstances are reminiscent of when Apple previously stopped releasing the Intel version of the Mac OS X kernel, which some had concluded was due to piracy concerns. Apple finally released the source at WWDC along with an apology for the delay, but did not give an explanation.