public Field or(String fieldName) {
        Field f = new Field(this, fieldName);
        f.setOp("or");
        queries.add(f);
        nonEmpty = true;
        return f;
    }
Or.
https://docs.vespa.ai/en/reference/query-language-reference.html#or

@param fieldName the field name
@return the field
client/src/main/java/ai/vespa/client/dsl/Query.java