[loeg]

This is all accurate. It's a FreeBSD 4 fork that targets amd64 exclusively. (The latest FreeBSD release is 12.0.)

That's not to say it is stale or anything like that; the BSDs share quite a bit of code heavily thanks to the license. And DFBSD has some novel things that FreeBSD does not have: in particular the SMP model is still distinct; they have the novel HAMMER filesystem, which no other operating system has; and they lead FreeBSD on DRM graphics drivers porting from Linux and non-uniform NUMA support (i.e., Threadripper 2990WX). There are certainly other things I am forgetting or simply don't know about; I develop FreeBSD and don't use Dragonfly myself.