Aris

CustomCSSforFx. Custom CSS tweaks for Firefox

CustomJSforFx. custom scripts

ClassicThemeRestorer. Classic Theme Restorer for Australis UI (Firefox/Waterfox/Basilisk versions 45.x-56.x only!)

CustomCSSforTb. Custom user styles for Thunderbird

Scrollbars. Custom Scrollbars (moved to CustomJSforFx)

CustomizeMyBird. Customize Thunderbird 52-60.x (no support for Thunderbird 68+)

NoiaButtons. NoiaButtons for Firefox Quantum