Man pages matching name curlopt_max_send_speed_large in section 3:

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