Man pages matching name knet_log_get_subsystem_id in section 3:

knet_log_get_subsystem_id.3.en	debian 10 / libknet-doc
knet_log_get_subsystem_id.3.en	debian 11 / libknet-doc
knet_log_get_subsystem_id.3.en	debian 12 / libknet-doc