bullseye-backports - xdm
The Vcs-* headers in the last upload of this package are still pointing to alioth (git://anonscm.debian.org/pkg-xorg/app/xdm,branch=debian-unstable) . However, Alioth has been turned off and its repositories are no longer directly accessible.
Please migrate the package to alioth's replacement, salsa and update the Vcs-* headers.