$ git clone -n https://src.fedoraproject.org/rpms/perl-Math-Random-Secure.git /var/lib/mock/f40-build-2239301-53610/root/chroot_tmpdir/scmroot/perl-Math-Random-Secure
Cloning into '/var/lib/mock/f40-build-2239301-53610/root/chroot_tmpdir/scmroot/perl-Math-Random-Secure'...
$ git fetch origin b63f7521afe1d53110a57b0cc99f2f44053ec56e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Math-Random-Secure
 * [new ref]         b63f7521afe1d53110a57b0cc99f2f44053ec56e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b63f752 Improvements to the spec file