Man pages matching name mongoc_stream_get_base_stream in section 3:

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