This was a bit of a surprise to me, but Apple released the xnu-2782.40.9 source code – among others – used in Yosemite 10.10.5 No idea if this happened before – not that I recall – but a new update of Yosemite may soon be released. Otherwise this is a totally unexpected move from Apple.
Oh and a new version of kext tools (384.30.2) is also available for download. Too bad that this isn’t the latest. Oh well. We can’t have everything at once.
Pike's Universum 
Interesting. It looks like they’re releasing once a year, roughly in the fall. So I guess we can’t expect any 10.11 kernel source code for a while.
Well. Apple only released Yosemite 10.10.5 in August… and there is hope that Apple will do the same for El Capitan , especially now that El Capitan 10.11.1 Beta is out for testing. Perhaps that will help them to release the XNU source code for El Capitan 10.11 earlier than usual.
I personally won’t be waiting for it. Not anymore. It’s there when it is there. I have my work covered already 😉