Window Names от Jim Thomas

A small Firefox extension that lets you give each browser window a custom name and color. The name shows up in the title bar, the taskbar/window switcher, and the macOS dock icon's window list — making it easy to tell windows apart when you have several open for different contexts (Work, Research, Email…).

Features

Name a window — set a custom name per window. It's prepended to the window title via windows.update({ titlePreface }), so it appears in: the OS title bar, the taskbar / window switcher, the macOS dock icon's right-click window menu.
Color a window — pick from a soft palette (the Firefox profile colors). The chrome is themed per window with a tasteful edge-gradient look: a narrow gradient strip is pinned to each side while a solid color fills the stretchy middle, so it resizes gracefully (the same technique the Alpenglow theme uses).
In-chrome confirmation — the toolbar button shows the window's name as a badge, tinted with the chosen color.