Manage private source of VIM3 on github


I want to manage my VIM3 source code on my private github account just like khadas is doing. Since I am not familiar with the procedure of generating android_manifest from a repo, I need your assistance in this regard.
So, I want to inquire that how khadas is generating and managing android_manifest for a particular repo on github?

Thank You.

@Terry @goenjoy

Will you please have a look at this??