Discourse. But given that you follow the stable branch, updating won’t due you much good until we release 2.3.0 stable, which won’t be for some time, or backport the changes. The commit you’re looking for is UX: Adhere to Facebook & Twitter brand guidelines for share icon colors · discourse/discourse@4178578 · GitHub, plus the changes to variables.scss in UX: Update brand color, some login adjustments · discourse/discourse@95e8c93 · GitHub.
Kris is out at the moment, but I wonder if this is safe to backpot to stable @Johani @zogstrip?