While iOS 7 beta 3 was certainly the biggest news today, Apple has also pushed another build of Mac OS X 10.9 Mavericks to developers. The latest build, which features various speed and stability improvements, is available as an update to those who already have the beta installed as a 1.08 GB download.
Mavericks will be available to the public this fall, and includes various improvements and tweaks to the operating system. The various features tend to be more about refining what OS X has become than breaking new computing ground; for example, Mavericks is promising improved performance and battery life by utilizing techniques such as timer coalescing to reduce the constant load on the CPU and GPU. The price for Mavericks is unknown, though it is likely to be the cheapest update to OS X yet.