Man pages matching name gnutls_dh_params_export_pkcs3 in section 3:

gnutls_dh_params_export_pkcs3.3.en	debian 10 / gnutls-doc
gnutls_dh_params_export_pkcs3.3.en	debian 11 / gnutls-doc
gnutls_dh_params_export_pkcs3.3.en	debian 12 / gnutls-doc