Just wondering why some of method calls like the following _toQuery(), which was found in public docs, have underscore prefixes. I also saw this in some packages like _types. Typically I see this done for internal usage, not for public APIs so I was a bit hesitant to use these, but apparently they're found in example code so it shouldn't be a problem. That still leaves the question of why were they named like that. TIA!
From Searching for documents | Elasticsearch Java API Client [8.12] | Elastic...
Query byName = MatchQuery.of(m -> m
.field("name")
.query(searchText)
)._toQuery();