WPT details: https://wpt.fyi/results/css/css-text-decor Not fully testable because it's a rendering feature.
This feature introduces 'text-emphasis', 'text-emphasis-color', 'text-emphasis-position', and 'text-emphasis-style' CSS properties. They are unprefixed versions of '-webkit-text-emphasis', '-webkit-text-emphasis-color', '-webkit-text-emphasis-position', and '-webkit-text-emphasis-style'.
Samples: https://developer.mozilla.org/en-US/docs/Web/CSS/text-emphasis