Man pages matching name curlinfo_condition_unmet in section 3:

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