$ git clone -n https://src.fedoraproject.org/rpms/git.git /var/lib/mock/f40-build-787453-134776/root/chroot_tmpdir/scmroot/git
Cloning into '/var/lib/mock/f40-build-787453-134776/root/chroot_tmpdir/scmroot/git'...
$ git fetch origin 4a9627d9cb50b188a28fa12782a9fe7419900774:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/git
 * [new ref]         4a9627d9cb50b188a28fa12782a9fe7419900774 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4a9627d update to 2.44.0