ifupdown has stopped providing /etc/network/run in 2012. Apparently on existing installs, the upgrade code did not work correctly so most existing installs still have the compatibility symlink.
-- ,''`. Christian Hofstaedtler <z...@debian.org> : :' : Debian Developer `. `' 7D1A CFFA D9E0 806C 9C4C D392 5C13 D6DB 9305 2E03 `-