Man pages matching name mongoc_server_description_round_trip_time in section 3:

mongoc_server_description_round_trip_time.3.en	debian 10 / libmongoc-doc
mongoc_server_description_round_trip_time.3.en	debian 11 / libmongoc-doc
mongoc_server_description_round_trip_time.3.en	debian 12 / libmongoc-doc