Prior to this update, YouTube Music is already equipped with a similarly named Your Mix playlist. However, the difference between the current playlist and the soon to be released version is that the current one inconveniently throws in all of your music altogether into one.
The My Mix feature, on the other hand, is being worked on to neatly categorise music into seven separate playlists. This will enable users to have more control over what they would want to listen to as opposed to a jumbled up collection of music being cluttered into an individual playlist. Based on reports from Android Police, the My Mix playlist has made its way to YouTube Music’s web client for some, and the mobile app for others. However, they have mentioned that none of their team members has managed to spot this feature at the moment. This could only mean that Google is testing this feature for a limited group of people, and may be planning a global rollout.
Regardless of the reasoning from Google’s side, it is still a waiting game until the company finally decides to make this feature live. That being said, we will keep you updated if additional information is released in the coming months regarding this feature. (Source: Android Police)