ECDH and ECDSA in PGP with known public key
Sounds like a description of ECIES to me. ECIES is a hybrid cryptosystem that builds upon ECDH.

Basically: the static public key of the receiver is used together with an ephemeral key pair generated at the sender. The public key of the receiver and ephemeral private key of the sender are used to generate a "shared secret" using ECDH. This shared secret is used with a KDF to generate a session key. This session key is used to encrypt the message. Then the ephemeral public key is attached to the ciphertext. The private key can be safely destroyed.

To decrypt the same secret is calculated at the receiver using the static private key and the public key attached to the ciphertext. The KDF is applied again to generate the session key. Then the resulting key is used to decrypt the ciphertext.

As you can see, after encryption the sender isn't needed anymore. So this scheme can be used to encrypt static data such as files. The only thing the sender needs is a trusted public key to the receiver. This public key is for instance embedded in the PGP certificate of the receiver.