Man pages matching name curlinfo_proxy_ssl_verifyresult in section 3:

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