I think this is an intended change; it was explained via a link
to a comment in another issue (I think by mame or someone else,
where matz commented on reverting the behaviour). If I remember
the reason, the changed backtrace confused many ruby users over
the years, and it seemed better to go back to the state prior
to the change, hopefully lessening the confusion in the
process. :D
(Not sure if NEWS mentions this, but if not then perhaps a link
should be there, or just a short explanation in NEWS itself.)