Man pages matching name curlmopt_pipelining_site_bl in section 3:

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