> Ruby, a form of interlinear annotation, are short runs of text alongside the base text. They are typically used in East Asian documents to indicate pronunciation or to provide a short annotation.
> This specification revises and extends the markup model established by HTML to express ruby.
The posted link is a short announcement. Here are the actual specs:
For those with some knowledge of the Japanese language, this is often used to display furigana in Japanese. I believe HTML Ruby derives from a once-proprietary Internet Explorer feature.
Very nice to see some progress here. I think "CSS Ruby Annotation Layout Module Level 1" saw most work around 2013/2014, there are also specifications for ruby that are part of XHTML and HTML 5 standards.
Even when ruby markup is popular with south-east asian scripts I mostly want to use it for interlinear text or textspan-level inline annotations for a software to learn languages.
I remember with the ruby specified in XHTML standard there were ergonomic issues when ruby is written, i.e. it's nice for interlinear text markup to not have to close HTML tags. Also there were issues where people did not understand what the differences between mono ruby, group ruby and jukugo ruby is (correct me if I remember it wrong).
Ruby seems to be not implemented well in browsers, some ruby-related tags were deprecated, the specification posted is part of the restoration of these tags [1]. But last time I checked there was interest of all major browser manufactors to implement ruby standard properly.