https://solr.apache.org/docs/7_4_0/solr-core/org/apache/solr/search/facet/FacetProcessor.html
FacetProcessor (Solr 7.4.0 API)
solrapi
https://solr.apache.org/docs/10_0_0/core/org/apache/solr/search/facet/FacetProcessor.html
FacetProcessor (Solr 10.0.0 core API)
declaration: package: org.apache.solr.search.facet, class: FacetProcessor
solrcoreapi