Man pages matching name gnutls_session_ticket_key_generate in section 3:

gnutls_session_ticket_key_generate.3.en	debian 10 / gnutls-doc
gnutls_session_ticket_key_generate.3.en	debian 11 / gnutls-doc
gnutls_session_ticket_key_generate.3.en	debian 12 / gnutls-doc