Man pages matching name curlmopt_max_pipeline_length in section 3:

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