META-INF / com / google / android / update-binary source code?

In the Update.zip file of the update file for Android, the update-binary version is present in the path META-INF / com / google / android / . The .zip update will be downloaded by the system, and later the update will be installed on the system. I need help understanding the binary update file and its use. Can any body help me with this, as well as with the appropriate source code? It will be good if any authority shares a link to the source code.