$ git clone -n https://src.fedoraproject.org/rpms/rxvt-unicode.git /var/lib/mock/f43-perl-60961525-6586810/root/chroot_tmpdir/scmroot/rxvt-unicode
Cloning into '/var/lib/mock/f43-perl-60961525-6586810/root/chroot_tmpdir/scmroot/rxvt-unicode'...
$ git fetch origin 5f015960c5930c16a807036877b675116a8f8bf9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rxvt-unicode
 * [new ref]         5f015960c5930c16a807036877b675116a8f8bf9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f01596 Perl 5.42 rebuild