One great new feature of the 0.2.5.x branch is support for Linux seccomp. There is a similar project that's cross-platform (FreeBSD, DragonFly BSD, Linux for now) called Capsicum.
It is a project supported by University of Cambridge Computer Laboratory, grants from Google, the FreeBSD Foundation and DARPA. Its goals are similar to seccomp, but the Capsicum project utilizes approaches quite different from how seccomp does things, potentially preventing a different set of attacks.
While the FreeBSD implementation is the furthest so far with Linux development still not being in mainline yet there are a number of applications (ping, tcpdump, gzip, Chromium (wip)) already supporting Capsicum. According to a presentation of the project adding support for Capsicum tends to be easier, than for adding seccomp support.
Is anyone working on this right now? Are there any plans on supporting it? And most importantly is there any reason to not support it?