Compared to the popular third-party alternatives, Android's stock recovery has always been pretty...weak. Makes sense, because it's not really meant to do all the stuff that ROM flashers tend to use recovery for, but rather a failsafe of sorts in case something goes awry.
With L's Android release, the recovery is getting a little bit more useful with two new options: reboot to bootloader and power down. Nothing groundbreaking here, but still incredibly useful (especially "reboot to bootloader") for those times when stock recovery is the only option.
Basically everything else is the same here: reboot device, update from ADB, factory reset, and wipe cache are all along for the ride. But what do you care – you're just going to flash TWRP anyway, right?
Thanks, Alexei Watson!