Re: A last missing link for interoperable representation

Source code is an example of plain text, and yet adding italics into
comments would require but a trivial change to editors. If the user
audience cared, it would have been done. In fact, I suspect there
exist editors and environments where an HTML subset is put into
comments and rendered by the editors; certainly active links would be
more useful in source code comments than italics.

Source Insight is a nice and powerful programming editor that supports rich-text display of source code, i.e. beyond simple syntax coloring / linkification.

For example, large type for function names.

They even support some styling in comments, but more along the lines of allowing their own markdown convention that let's you write headings of different levels.

Both to write comments that introduce sections of your code, as well as headings and subheadings inside longer comment blocks.

So stuff like that exists, but it's using semantic markup (style settings per language element) or markdown (styles in comments).

A./