While Apple has claimed to be a significant contributor to various open-source projects in the past, many of its technologies are still closed source. However, the Cupertino giant has now made a big move by releasing the source code of the XNU kernel which powers its flagship operating systems, on GitHub.
XNU, which is an abbreviation of 'XNU is Not Unix', is a Unix-like kernel used in macOS, including all the previous versions of the OS, when it was known as OS X, as well as iOS. By giving access to the kernel code, Apple has made it easier for developers to understand how devices and upper layers of software work with the kernel. It is not yet clear how much more the developers can benefit from this release, but it could be one of many steps taken by the company to attract developers.