Mozilla is experimenting with interesting things

Test Pilot is essentially the foundation’s sandbox, where the latest experiments take place.

This is a good thing because it allows us to see months before what innovations we can expect; Color and Side View.

As the name suggests, Color is designed to add color to Firefox, allowing you to easily transform the color scheme of your browser (tabs, icons, title bar, etc.). The foundation offers a number of unique themes, but of course we can share our own materials with the community ourselves.

Side View may be of interest to users with larger sizes; the plug-in can display multiple tabs at once. A site located in the sidebar brings up a mobile view of that page, if available. When the add-on is active, we can send the given web page to the sidebar with one click - this is e.g. can be useful for social networking sites.

It’s important to note, these new features are just experiments, by no means certain to appear in the main version.

Source: techspot.com