[galvin]

I think this is a new function. Probably made just for the rune bar for deathknights.

From my quick testing is instead of a cooldown having a square border. It has a round border.
Blizzard no longer has to use tricks to fake a real circle cooldown. Hopefully they expand on this and use it in other parts of the games UI.

Is there a way to find new functions added, only stumbled across this one looking at the xml. Then I had to guess what the lua function was. In the xml its called useCircularEdge

I'm liking this a lot, cooldowns have gotten so many new features over the years. Keeps getting better.