WPT details: Some of https://wpt.fyi/results/css/css-ruby and https://wpt.fyi/results/css/css-display/parsing
New CSS display property values, "ruby" and "ruby-text", are added. The default display values of <ruby> and <rt> are changed to "ruby" and "ruby-text" respectively, and ruby layout respects these display values. Web authors can use any elements such as <div> to render ruby by setting the new display values.