log-structured filesystem in netbsd : still there?

[Mayuresh Kathe]

there used to be a filesystem called the log-structured filesystem
which was a great idea but poorly implemented in 'bsd'.
i have heard that freebsd and openbsd have opted to remove it, but
netbsd kept it active and even continued development on it from
4.x onwards.
is it true? what is that filesystem called in netbsd source?
how do i get to read up more on it, other than reading the source?