... Surprise!This is the same style ZKL always used, you could toggle it on/off with a blue button in the upper right. The button was removed and this style made default.
Licho thought people would prefer it. I am sure that this change is by no means to be considered final.
For anyone wondering, this change included an incomplete(!) wiki feature. That was an accident and not intended to go live just yet. Both these things are part of a large number of patches that were all forwarded from test.zero-k.info to zero-k.info in one big push.