Re: a :time pseudo-class for media elements (and examples on how it would be useful and generic)

The initial idea disregards that videos should support different languages
for subtitles. Also I don't see a :time pseudo-class but only some numeric
"pseudo-classes".
When reading about such a pseudo-class I imagine something like this:

#myVideo:time(23.48s-28.12)::after {
  content: "I love this part of the video";
}

Another use case would be to show a popup with info to the video or a link
to a similar video at a specific time.
By skimming through the MSDN article I don't believe that's covered by the
<track> tag.
So allowing to style the video depending on time using CSS would give more
flexibility.

    .video-related {
>         animation-time-source: url(#videoID);
>     }
>
François, could you elaborate on that? I don't seem to get where the
relation to the time is defined.

Sebastian