Search domain support in 10.10.1 / no mention in man discoveryd

The release notes for 10.10.1 include:

Allows you to append search domains for partially qualified domain names when performing DNS lookups (consult the discoveryd man page for more information)

But there is no mention on this in the discoveryd(8) man page (and not in discoveryutil(8) either).

Is this actually included in 10.10.1, if so, where can one find information on it?