Man pages matching name gnutls_pkcs11_privkey_export_pubkey in section 3:

gnutls_pkcs11_privkey_export_pubkey.3.en	debian 10 / gnutls-doc
gnutls_pkcs11_privkey_export_pubkey.3.en	debian 11 / gnutls-doc
gnutls_pkcs11_privkey_export_pubkey.3.en	debian 12 / gnutls-doc