[wp-hackers] do_favicon equivalent to do_robotstxt?

[Ken (WraithKenny)]

I was attempting an "apple-touch-icon" and favicon functionality for a
theme, but evidently, "apple-touch-icon" needs to reside at root; The
meta tag in head doesn't work. (Also, there was a discussion on
[theme-reviewers] Themes and Favicons.) This is problematic because as
far as I know, plugins and themes can't/shouldn't be writing there.

Then I came across the do_robotstxt and it occured to me that a
version for favicons or sitemaps or anything else would be rather
useful for those cases, as then when a plugin or theme is no longer
active, there effects would disappear. From what I gather,
do_robotstxt simulates the file rather then creating a real file in
root.

Should something like do_robotstxt for favicons/sitemaps/etc be
implemented in core for general convienence or is this still something
belonging to plugins/themes and that plugin/theme devs should work out
for themselves?