FreeBSD 10.3 is in the "release builds" phase. See: https://www.freebsd.org/releases/10.3R/schedule.html

Barring anything crazy, I imagine it will be officially released in a couple of days.

I probably should have mentioned that, but I guess I was trying too hard to be pithy. When I looked, a 10.3-RELEASE branch/tag didn't exist, but based on the schedule and last commit I assumed the source was frozen.

Anyway, I was only half-joking; it actually is fairly impressive to be able to leapfrog the FreeBSD process in this way, even if some of the difference comes down to differing requirements and priorities.