Jean-Paul, to find out why the specific patch was not backported, you
would have to ask the original committer (which happens to be Georg
Brandl). If you want to ask that question through the tracker, it's best
to add him to the nosy list, so that he can actually see that he is
being asked a question.

My guess is as good as everybody else's: most likely, he didn't have the
time to backport, or didn't consider it important enough.