I don't follow the lyrics search results too closely but back in 2014 Google added full lyrics to their search results. Since they added translation features to it last year. Now, according to Glenn Gabe they redesigned the mobile interface for the lyrics to be in this panel like UI.
Glenn Gabe posted on Twitter "Pretty sure this is a new mob SERP for song/lyrics searches. Now joins other categories for immersive mobile SERPs. Instead of just lyrics (which was huge), now you have multiple tabs for overview, lyrics, listen, similar songs, & other recordings."
Here is a screen shot:
You can try it on mobile for your favorite songs - the color of the background changes by the artist.
Forum discussion at Twitter.
