At this year’s Google I/O 2017, Google announced a lightweight version of its Youtube App that should allow allow offline Youtube Video downloads. A good use case would be downloading your favorite Youtube videos on fast public WiFi and then watching them at home. The app also enables sharing of downloaded Youtube videos with nearby friends without needing an internet connection. We assume it would work similar to how file-sharing apps like Xender work — WiFi Direct/Bluetooth connections.
Previously Google offered Youtube offline in its officially app only through select countries such as Kenya, Nigeria, Philippines, India, Ghana etc cutting off a big percentage of the developing world that need the service.
The Youtube Go app is on the Google play store although currently only officially available in India. So I had to use third-party stores, AppMirror to download the App to my phone as an APK and manually install. The app is only about 8MB in size, which is really small.
It seems users have to wait till the app leaves beta stage, perhaps by then Google would have rectified the Download issue. Until then you have to use a number of Youtube downloaders.