From memory, this is the first release of the Darwin source in ages, but https://opensource.apple.com/ looks to have been updated.

http://www.puredarwin.org/ looks abandoned, and OpenDarwin disappeared long ago - http://www.applematters.com/article/opendarwin-dies-a-lonely...

> From memory, this is the first release of the Darwin source in ages

Ages? https://opensource.apple.com/ looks like it has for a while, except for the addition of 10.10 (I grab CFLite, libclosure, libdispatch, and objc4 whenever they're made available after a release).

Not in a very long time. If memory serves, Apple last released a bootable image for one of the Darwin 8.x releases.