"Only applicable for phones with Xperia™ Style portrait app in Camera.
Style portrait helps you to create a different you by applying your favorite styles when taking portrait photos.
The styles may include face effects, color filters, and deco frames.

Add Bubble style effect to Xperia™ Style portrait application.
With Bubble style effect you can have this real-time style in your viewfinder.
The style of Bubble can be managed and edited in style collection.
Copyright © 2015 Sony Mobile Communications Inc."

From version Bubble 29.1.A.0.1:
All versions
March 1, 2017
October 18, 2016
January 28, 2016