A dark indigo CSS theme for Firefox and a large collection of privileged scripts to add new buttons, menus, and behaviors and eliminate nuisances. The theme is similar to other userChrome stylesheets, but it's intended for use with an autoconfig loader like fx-autoconfig, since it uses JavaScript to implement its more functional features.
I used a frame script to speed things along and facilitate development, but it's not ideal. Switch to a JSWindowActor like searchExtensionShortcut.