chromium/third_party/blink/web_tests/external/wpt/webvtt/rendering/cues-with-video/processing-model/support/line_integer_and_percent_overlap.vtt

WEBVTT

00:00:00.000 --> 00:00:10.000 line:9
This is a test subtitle

00:00:00.000 --> 00:00:10.000 line:50%
This is another test subtitle