$ git clone -n https://src.fedoraproject.org/rpms/python-matrix-common.git /var/lib/mock/f45-build-31513-652/root/chroot_tmpdir/scmroot/python-matrix-common
Cloning into '/var/lib/mock/f45-build-31513-652/root/chroot_tmpdir/scmroot/python-matrix-common'...
$ git fetch origin 2713acd9cdf4a3a71dd7cdc950c0bad1af38ca14:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python-matrix-common
 * [new ref]         2713acd9cdf4a3a71dd7cdc950c0bad1af38ca14 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2713acd Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild