Google makes changes to the Library tab UI on the Android and iOS variants of the YouTube app
As per 9to5Google, if you tap the Library tab found on the iOS and Android YouTube app on the bottom of the screen, you might now see two carousels. One shows a history of the YouTube videos that you've been watching and underneath that is a carousel that shows your YouTube Playlists. That is a change from the previous look of the YouTube UI which showed your Playlists in a vertical list that you could scroll down to see.
With the new carousel version of your YouTube Playlists scrolling horizontally, the Library tab is now much shorter. On the Playlists carousel, the first preview shows you all of those videos you agreed to "Watch later" with the number of such videos shown underneath a clock icon on the preview screen. Tap on the preview screen and you're sent to the Watch later YouTube page with all of the videos you chose to "Watch later" presented in a vertical list. A three-dot menu next to each listing allows you to save the video to the playlist, remove it from Watch later, or share it.
The new UI for the Android and iOS YouTube Library tab
The second preview screen is for "Liked videos" with the number in that list shown underneath a thumbs-up icon. Tap on the preview and you'll be sent to the Liked videos page with all of the videos you like displayed in a vertical list. The three-dot menu to the right side of each listing allows you to save each video you liked to the Watch later list, save each liked video to your playlist, share a video, or remove it from Liked videos.
The next few preview screens (up to 8) are for your You Tube Playlists. For example, this writer has a playlist made up of iPhone ads and another that consists of iPhone unveiling events. Tap on one of the preview screens and you'll be sent to a page that shows all of the videos that are part of that particular playlist. Tap the three-dot menu to save the video to Watch later, save the video to a separate playlist, remove the video from the current playlist it is in, or share it.
The new UI might not be available yet for all Android and iOS users but it is on my Pixel 6 Pro running QPR3 Beta 3. If you don't have the YouTube app on your phone, you can install it on your Android device by tapping on this Play Store link. Install it on your iPhone by tapping on this App Store link.
Things that are NOT allowed: