Unreal Engine 4 - Source controll


I have some questions about how Epic handle version control of his engine.

If I download source code from, it also needs to download other
dependencies (binary assets I suppose) from somewhere else…

What kind of model is this? Text/Source code files on GitHub and binary
assets on e.g. Amazon S3? How can I acomplish this or something similar
on my personal project?

Thank you for your reactions and ideas,

M. M.