This is a very standard way libraries have been presenting their speed comparison for quite awhile now.  You can look at the individual slivers to get a rough estimate of the size difference, and overall cross browser comparison, and see which browsers are the slowest.<p>It's a very good visualization, letting one compare the same browser across two version of jquery, an aggregate of browsers across both versions, and the speed of individual browsers against each other on the same version, and individual speeds across the different versions.  It's very data packed.