I believe the most significant/major one was the progress slider, as outlined here
There were a few more, regarding the bell/notifications function, I believe. I’ve never used it, as I wanted a fresh look with full functionality, and frankly the best, FULLY functional one is Discourse default, which I used during BerserkerDay but still use WB Default most of the rest of the time (I can’t do some Admin functions in WB default as I can in Discourse Default, which is more stark white)