Man pages matching name bson_json_data_reader_ingest in section 3:

bson_json_data_reader_ingest.3.en	debian 10 / libbson-doc
bson_json_data_reader_ingest.3.en	debian 11 / libbson-doc
bson_json_data_reader_ingest.3.en	debian 12 / libbson-doc