Sony is continuing its odd support for modifications and software based on Android's open source core. Today they're releasing a collection of flashable recovery partitions for some phones - technically these count as "custom" recoveries, but they're based on AOSP, and therefore pretty close to what you'd find on Nexus devices. Sony's intro video does state that the recovery can restore data, flash custom ROMs, and boot to multiple ROMs, something that most stock recoveries can't handle.
The new recovery is available on the Xperia Z1, Xperia Z1 Compact, Xperia Z Ultra, Xperia T2 Ultra, Xperia T3, Xperia M2, and Xperia E3, all of which need to be unlocked at the bootloader level and running the latest "generic" software from Sony. As nice as it is to see Sony continue its support of the development community, I can't help but think this recovery doesn't serve much of anyone - if you want to run Sony's AOSP builds of Android itself, you can just use the existing flash tool. And if you're more interested in the wide world of custom ROMs, odds are that you've already installed ClockworkMod or TWRP.
A full set of instructions and downloads is available on Sony's developer blog. Be prepared to say goodbye to your warranty, but don't worry - there are so many resources for Sony phones at this point that permanently bricking one might be some kind of video game-style achievement.