presto-main/src/main/java/io/prestosql/sql/planner/planprinter/TextRenderer.java/TextRenderer/translateOperatorTypes
class TextRenderer:    private static Map<String, String> translateOperatorTypes(Set<String> operators)
    {
        if (operators.size() == 1) {
            // don't display operator (plan node) name again
            return ImmutableMap.of(getOnlyElement(operators), "");
        }

        if (operators.contains("LookupJoinOperator") && operators.contains("HashBuilderOperator")) {
            // join plan node
            return ImmutableMap.of(
                    "LookupJoinOperator", "Left (probe) ",
                    "HashBuilderOperator", "Right (build) ");
        }

        return ImmutableMap.of();
    }