$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-BigInt-FastCalc.git /var/lib/mock/f45-build-24672-605/root/chroot_tmpdir/scmroot/perl-Math-BigInt-FastCalc
Cloning into '/var/lib/mock/f45-build-24672-605/root/chroot_tmpdir/scmroot/perl-Math-BigInt-FastCalc'...
$ git fetch origin a7cbd1b59df0e3a8d8c369788c1fd95449592ec3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-BigInt-FastCalc
 * [new ref]         a7cbd1b59df0e3a8d8c369788c1fd95449592ec3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a7cbd1b Increase release to favour standalone package