$ git clone -n https://src.fedoraproject.org/rpms/perl-XML-Fast.git /var/lib/mock/f45-build-27476-624/root/chroot_tmpdir/scmroot/perl-XML-Fast
Cloning into '/var/lib/mock/f45-build-27476-624/root/chroot_tmpdir/scmroot/perl-XML-Fast'...
$ git fetch origin c2c8159d608d13fe6b97e55c9f45019fae1df13a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-XML-Fast
 * [new ref]         c2c8159d608d13fe6b97e55c9f45019fae1df13a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c2c8159 Perl 5.44 rebuild