defined(my $s = $opt->{$k} // $cfg->{lc($git_key)}) or next;
defined(my $v = $cfg->git_bool($s))
or die "`$git_key=$s' not boolean\n";
defined(my $s = $opt->{$k} // $cfg->{lc($git_key)}) or next;
defined(my $v = $cfg->git_bool($s))
or die "`$git_key=$s' not boolean\n";