Personas for Firefox is a firefox extension that adds lightweight theming to your browser. It is a fun way to personalize your browser further, and is based on the premise that graphic designers should be able to style the browser without having to code…
After you install Personas and select a theme from the over 50+ themes that the little fox presents, the theme background changes instantly in both the upper panel and lower status bar. Note that the icons do not change like in a full theme change, only the background does. You have nothing to download or install, and no restart is required. You can always switch back to the default Firefox theme.
How does it work so fast? They explain that the Persona selector is dynamically loaded and populated from a JSON feed and all designs are loaded via URLs to remote resources. All changes to the browser chrome are applied instantly, with no need to restart.
Mozilla plans to release an API that will allow developers and designers to submit Personas that are based on Web content. Then Personas can be added, removed or updated by their designers at any time, without requiring a software update.