The new Firefox introduces a new tab shape that is consistent with Firefox for Android, FirefoxOS, Thunderbird, as well as the web properties of Mozilla.

Firefox for Android

Firefox

As the Firefox team was implementing this new design, performance was a key metric that was measured and focused on. We wanted to not only bring a beautiful design to users, but one that matched the new sleek shape with an equally speedy outcome.

Each time a change was made to our source control repository, a fresh build of the browser was created and run against a suite of automated tests that measure the performance of the build. These results are then compared against the results of prior builds, allowing the team to track…