Man pages matching name curlopt_socks5_gssapi_service in section 3:

CURLOPT_SOCKS5_GSSAPI_SERVICE.3.en	debian 10 / libcurl4-doc
CURLOPT_SOCKS5_GSSAPI_SERVICE.3.en	debian 11 / libcurl4-doc
CURLOPT_SOCKS5_GSSAPI_SERVICE.3.en	debian 12 / libcurl4-doc