Man pages matching name gnutls_crypto_register_aead_cipher in section 3:

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