Since learning that one can give Prettify language hints, I've
been quite careful to specify such whenever I post code in a
non-default language; however, out of laziness (or conciseness),
I've omitted explicit hints whenever my code uses the then-
current default.  On occasion, I've noticed that a question's
tags have been edited after my post, resulting in a different
and unintended formatting being applied.  I was about to suggest
that the default language at the time of a post be retained
through tag edits, but then I discovered that a certain "Jon
Skeet" (of course; who else?) did that years ago. Despite the
numerous upvotes, it seems his suggestion never got implemented
(perhaps because the question was only a rather than a , or
perhaps because it has since been locked).  Mr Skeet noted that:
I propose that upon being first submitted, SO automatically
prepend every post with a <!-- language-all: ... --> hint;
subsequent edits would then be able to modify the default if so
desired.  Historical posts cou