What is LRC?

The lyrics format, from the days of ripping CDs. One timestamp per line and no end times at all, because a music player only needs to know when to highlight the next line. That missing end time is the thing that complicates every conversion out of it.

What is WebVTT?

The subtitle format built for HTML5 video - what a browser loads into a track element. It's SRT with a header, a full stop instead of a comma in the timestamps, and optional positioning and styling that most people never touch.