$ git clone -n https://src.fedoraproject.org/rpms/pepc.git /var/lib/mock/f40-build-2014806-46013/root/chroot_tmpdir/scmroot/pepc
Cloning into '/var/lib/mock/f40-build-2014806-46013/root/chroot_tmpdir/scmroot/pepc'...
$ git fetch origin f1de97c105ee72bc383c902be743ce1d13a580e5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pepc
 * [new ref]         f1de97c105ee72bc383c902be743ce1d13a580e5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f1de97c Update to 1.4.37