$ git clone -n https://src.fedoraproject.org/rpms/docker-distribution.git /var/lib/mock/f38-build-side-42-init-devel-1087300-30040/root/chroot_tmpdir/scmroot/docker-distribution
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1087300-30040/root/chroot_tmpdir/scmroot/docker-distribution'...
$ git fetch origin 02d8f6fccc341adda6853147710ed3dd06cdd25d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/docker-distribution
 * [new ref]         02d8f6fccc341adda6853147710ed3dd06cdd25d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 02d8f6f Update to 2.8.1. Fixes rhbz#2043860