I was surprised to find that UninvertedField is no longer used in Solr. The only references to UninvertedField is from the fieldValueCache inside SolrIndexSearcher and that itself is not used anywhere in SolrIndexSearcher except for initialization and regeneration. I can't trace when Solr stopped using this class but in any case, we should remove it.
In a related note, Lucene's DocTermOrds has a copy of the class level javadocs of UninvertedField (which extends DocTermOrds). This was done in in