chromium/third_party/blink/web_tests/external/wpt/webvtt/rendering/cues-with-video/processing-model/selectors/cue-region/support/test.vtt

WEBVTT

REGION
id:1
lines:1
regionanchor:0%,0%
viewportanchor:0%,0%

00:00:00.000 --> 00:00:05.000
This is a test subtitle

00:00:00.000 --> 00:00:05.000 region:1
This is a test subtitle