$ git clone -n https://src.fedoraproject.org/rpms/libXmu.git /var/lib/mock/f45-build-15784-479/root/chroot_tmpdir/scmroot/libXmu
Cloning into '/var/lib/mock/f45-build-15784-479/root/chroot_tmpdir/scmroot/libXmu'...
$ git fetch origin 2a60f0aeb0d330ac4339f3112b71fef44fa9714f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libXmu
 * [new ref]         2a60f0aeb0d330ac4339f3112b71fef44fa9714f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2a60f0a Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild