Man pages matching name curlopt_tlsauth_type in section 3:

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