$ git clone -n https://src.fedoraproject.org/rpms/perl-UNIVERSAL-ref.git /var/lib/mock/f31-build-45018-26250/root/thebuilddir/tmp/scmroot/perl-UNIVERSAL-ref
Cloning into '/var/lib/mock/f31-build-45018-26250/root/thebuilddir/tmp/scmroot/perl-UNIVERSAL-ref'...
$ git reset --hard b78f685dd639817076a52cc3e7759715d957f65d
HEAD is now at b78f685 Perl 5.30 rebuild