chromium/third_party/blink/web_tests/external/wpt/html/semantics/embedded-content/media-elements/track/track-element/resources/cue-id.vtt

WEBVTT
Random text is accepted for cue identifiers.

random_id
00:00:00.000 --> 00:00:30.500
Bear is Coming!!!!!

another random identifier
00:00:31.000 --> 00:01:00.500
I said Bear is coming!!!!

identifier--too
00:01:01.000 --> 00:02:00.500
I said Bear is coming now!!!!

identifier--too
00:02:01.000 --> 00:03:00.500
Duplicate identifier