The last time we talked about live lyrics in YouTube Music was in April of this year. It's clear now that the rollout of the feature then was only a very, very limited test for a tiny group of users. Almost no one received the feature then, which we know because everyone actually received it this week.
Folks starting noticing the lyrics tab showcasing a live, listen-along experience over the past day or so and it really seems to be on everyone's account. I'm seeing the live lyrics on both android and iOS, so google appears to have pushed it everywhere. It's funny, because this is a pretty big feature and it just quietly rolled out to everyone rather than it receiving a big announcement.
To see the live lyrics for yourselves, you'll head into YouTube Music, play a song, and tap on the “LYRICS” tab at the bottom. That tap will expand the Lyrics tab to show the lyrics of the song you are playing, assuming it is supported (not all music is). The lyrics will then light up or highlight as they are mentioned within the song.
It's neat, right?
For those curious, I'm on version 6.15.51 on Android and 6.16 on iOS.
Google Play Link: YouTube Music