The following functions take "opts" and have no documentation about what "opts" are accepted:

• mongoc_client_find_databases_with_opts
• mongoc_client_get_database_names_with_opts
• mongoc_collection_find_indexes_with_opts
• mongoc_database_find_collections_with_opts
• mongoc_database_get_collection_names_with_opts

Document common fields that the C Driver parses from these functions' opts. The most important is sessionId, which permits some of these functions to be used in a transaction, and some of them to participate in causal consistency . Do not document fields that the server parses from opts, that documentation is in the MongoDB Manual only.