Man pages matching name mongoc_gridfs_file_get_chunk_size in section 3:

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