Jonathan Rees kindly released the W7 security kernel from his paper on capability security via the lambda calculus as free software. Awesome!

Jonathan describes W7 as very small because it's mostly just an environment for Scheme 48, but I consider that a feature... it gives me some hope that I might be able to implement similar things for Guile.

(It's released under CC0, I've asked for a patent disclaimer to be added to it, hopefully that'll happen shortly.)