UnrealEngine: cloned Repo from GitHub says "Empty Folder"

Hi Everyone,
I had been trying to download UnrealEngine Source Code from EpicGame’s GitHub Private Repo.

I’ve already cloned “release” branch three times using Git Bash (using command: git clone https://github.com/EpicGames/UnrealEngine.git) and GitHub Desktop too, since yesterday. Each time the cloning gets finished and the cloned folder in my PC “UnrealEngine” says “Empty Folder”… I don’t know why this is happening ?

I can’t also download Zip format, it getting only 25Mb downloaded and Says “Windows Can’t open this file. This file might be corrupted” . Please help me. I can’t download UE 4.19 using EpicLauncher, because I’m having a very poor Internet connection.