Yes, I saw that. Dolphin icon in Plasma and folder icons inside Gwenview (and probably other places) are black. Curriously enough, folder icons *inside* dolphin itself and in file browsing popups are fine.
That’s the only issue I could find now that we’re running a dual kf5+kf6 stack and I don’t consider it a blocker.
I’m betting on a small breakage of backwards compatibility in breeze-icons (which is supposed to be backwards compatible), or maybe just in our packaging ? If someone can analyse and find a fix I’m willing to upload it. But I won’t look into it myself, it’s both transitional and cosmetic issue and there are more important things to do.
It’s fixed in Plasma 6 which is not 100% ready for unstable prime time yet.