Man pages matching name curlopt_ssh_host_public_key_md5 in section 3:

CURLOPT_SSH_HOST_PUBLIC_KEY_MD5.3.en	debian 10 / libcurl4-doc
CURLOPT_SSH_HOST_PUBLIC_KEY_MD5.3.en	debian 11 / libcurl4-doc
CURLOPT_SSH_HOST_PUBLIC_KEY_MD5.3.en	debian 12 / libcurl4-doc