I would like to suggest adding some (optional) support for "Operating
System Commands" [1] to comint.  (This is unrelated to having Emacs
talk OSC codes with the terminal inside of which its running.)

This class of control sequences serves various random purposes, for
instance adding clickable hyperlinks in terminal applications.  As an
example, compare `ls --hyperlink' in the Emacs shell versus some other
"modern" terminal emulator.

Now, I don't particularly care about those hyperlinks or any other
established use of OSC sequences, and I guess a well-made program will
avoid outputting them to Emacs, since it advertises itself as a dumb
terminal.  But OSCs seem to be good a way to create ad-hoc communication
protocols between Emacs and other programs, say to display images in a
REPL buffer (see [3] for a precedent).

Thus, concretely, the suggestion is to add the
`comint-osc-process-output' function attached below to comint.el or some
other appropriate place.  It would not be added to
`comint-output-filter-functions' by default.  The hyperlink handler is
added as an example, it might be kept or removed.

Anyway, as an illustration, after evaluating the attached file and calling

  (add-hook 'comint-output-filter-functions 'comint-osc-process-output nil t)

in a shell buffer, `ls --hyperlink' should produce clickable
hyperlinks, as it does in other capable terminals.

What do you think?