All classes that implement SearchApiFacetSourceInterface in Facets 8
- class \Drupal\facets\Plugin\facets\facet_source\SearchApiBaseFacetSource implements SearchApiFacetSourceInterface
- class \Drupal\facets\Plugin\facets\facet_source\SearchApiDisplay implements SearchApiFacetSourceInterface
- class \Drupal\jsonapi_search_api_facets\Plugin\facets\facet_source\JsonApiFacets uses PluginDependencyTrait