The theme used to look like how the default dark theme looks on Firefox - no bright border around the tab; just a gray-ish current tab next to black/dark inactive tabs.
How it looks now on Windows/Firefox 93.0:
The new border looks very distracting. I can understand its usage as an accent color in other variants, but "Matte Black" should not have any white border.
Theme in question: https://addons.mozilla.org/en-US/firefox/addon/matte-black-v1/
The theme used to look like how the default dark theme looks on Firefox - no bright border around the tab; just a gray-ish current tab next to black/dark inactive tabs.
How it looks now on Windows/Firefox 93.0:
The new border looks very distracting. I can understand its usage as an accent color in other variants, but "Matte Black" should not have any white border.