I just reported a minor but visually major issue in plonetheme.barceloneta. And right after doing that, discovered another tab UI regression in patterns config UI.
That lead me to questioning the simple !important fix I proposed; I have no idea whether that fix will end up causing breakage somewhere else (it should not, and, fwiw, the same fix has been committed to the newer SCSS version of barceloneta).
So... does Plone have / use any kind of visual regressions testing? I believe e.g. BrowserStack could be used for that, and they have a free OSS plan...?