Here is some copypasta from the wiki.

This is the repository that stores all of AOSC OS build configurations, using ABBS (AutoBuild Build Service, deprecated) or ACBS (Autobuild CI Build System). This repository contains configurations of AOSC OS ports to a variety of architectures (x86_64, armel alike).

For more than three years (from late 2011 to currently season 2 of 2015), AOSC OS has been built with Autobuild - however - without any recording and enforcement of build process. The worst of all, although patches and source modifications are recorded, no source link was provided. And consequently raises skepticism from our users and inside of the development team.

With this repository, all packages in AOSC OS will be recorded in the new "abbs tree" model that includes source code specs (that includes download link for the source code, and the versions), and unified configurations for various architectural ports.

• Read the wiki please!
• Always push commits to the testing branch, the stable branch is only for tested commits with fixes (where necessary) from the testing branch, more in the wiki (again).
• Non AOSC-Dev members are also welcome to open PRs (pull requests) for this tree, but to the testing branch only.
• If your network condition is poor or you want to clone this huge repository quicker, please consider using our git bundles, see here for more information.