Man pages matching name curlopt_suppress_connect_headers in section 3:

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