Not about BSD, but anybody else using side tabs in FF with that site? Somehow the rendering of that dashed line at the top runs across into the "pinned tabs" section. (Linux/Wayland/Debian). Curious if anyone else is seeing it.
I just tried opening it (Linux/Wayland/Arch, and I already had number of tabs pinned to the side on Firefox), and I don't seem to have the same issue. I do have some custom styling in my Firefox though (legacy userChrome.css) and have it using my system theme, so that might cause some difference in addition to whatever differences might be in our compositors (not sure if yours is using kwin; I'm also guessing we prob…
EDIT: This is weird. My monitor has different modes including sRGB. I had it in a gaming mode (higher contrast, etc...) and it shows then, but in sRGB it doesn't show.
I took screenshots and when viewing there, regardless of screen mode, it's rendering fine, so clearly it must be a monitor issue of some sort. Odd that it would render in every non-sRGB mode, but be fine in sRGB.