Guide for sync'd lyrics?

[johnson]

I was looking at these two PRs (PR 1 and PR2) and want to know how to set this up. I can get static lyrics set up just fine, but would like to use the sync'd lyrics feature. What service provides the timestamps? Is the lyrics-lookup API built into JF to import the *.txt file? How can users implement this feature.

Is there a tutorial/guide/how-to on this that someone can point me to? I did a forum search but didn't find anything.