The feature, which inverts the colour scheme so that the background is black with text picked out in white, is created to reduce eye strain and to make using the app in low-light conditions more pleasant.
If you do not want to make use of the new feature, there is an option to turn it off and remove the prompt. Also, anything previously white will be converted into the dark theme, including search pages, backgrounds, tabs, and even the minimized video player.
The dark theme allows a user to tone down the screen's glare and experience YouTube with a dark background.
If you'd like to check and see if you have dark mode for YouTube, go to your app's settings, then "General". It's not clear if Google has enabled the dark theme on all Android devices just yet, but it is available on at least some of them. For example, viewing YouTube in a room with dim light does not leave any strain on your eye. But now most applications are coming with Night Modes which are activated as soon as the darkness falls. However, the wait of Android users is finally over, as YouTube's Dark Mode is finally rolling out for the Android app. Here you will find the switch to the dark theme. The change was rolled out last Friday by the Google owned video streaming side.