YouTube is testing the Smart Download feature for its videos, just like YouTube Music. This feature is being tested in the Android app.
Due to this feature, users can automatically download videos if their Android device is connected to Wi-Fi. If connected to Wi-Fi, 20 videos can be downloaded autonomously every week.
Offline content can be found from the Downloads page or from the Library tab. A similar feature is also available in YouTube Music. This feature will be very helpful in places with low data plan or poor internet connection.
This feature works on the latest version of Android. This feature is currently under testing and only available to some users in Europe.