$ git clone -n https://src.fedoraproject.org/rpms/perl-Capture-Tiny.git /var/lib/mock/f40-build-2212491-52270/root/chroot_tmpdir/scmroot/perl-Capture-Tiny
Cloning into '/var/lib/mock/f40-build-2212491-52270/root/chroot_tmpdir/scmroot/perl-Capture-Tiny'...
$ git fetch origin b7cf2e1e995430d709dfc93e25f0e86fa13e4904:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Capture-Tiny
 * [new ref]         b7cf2e1e995430d709dfc93e25f0e86fa13e4904 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b7cf2e1 Update section %%files