Apple has released an early version of Safari 4 (5526.11.2) to developers. This version is part of the release plan for Apple's Mac OS X 10.6 (Snow Leopard), focusing on improving performance and quality. In the official details released about Snow Leopard, Apple revealed that the bundled version of Safari will have "the fastest JavaScript speed in history, with a 53% improvement, making Web 2.0 applications respond more quickly."