/usr/share/xen-tools/intrepid.d/20-setup-apt is in xen-tools 4.6.2-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/xen-tools/intrepid.d/../common/20-setup-apt
/usr/share/xen-tools/intrepid.d/../common/20-setup-apt