$ git clone -n https://src.fedoraproject.org/rpms/perl-Algorithm-Diff-XS.git /var/lib/mock/f43-perl-60959185-6586769/root/chroot_tmpdir/scmroot/perl-Algorithm-Diff-XS
Cloning into '/var/lib/mock/f43-perl-60959185-6586769/root/chroot_tmpdir/scmroot/perl-Algorithm-Diff-XS'...
$ git fetch origin 14cf8e96a1aa81edab8e7f390fb873d72d2cb240:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Algorithm-Diff-XS
 * [new ref]         14cf8e96a1aa81edab8e7f390fb873d72d2cb240 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 14cf8e9 Perl 5.42 rebuild