Man pages matching name mongoc_gridfs_bucket_download_to_stream in section 3:

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