At a high level, DIDComm encompasses multiple layer in order to exchange verifiable, symantically coherent data between one or many parties. From a architecture standpoint there's multiple layers that go into building DIDComm.
This library focuses on the cryptographic layer of DIDComm which handles encryption and signing of an arbitrary message. It does so using a JWE like structure for encryption and a compact JWS for non-repudiable signatures.
To learn more about the data model used for encryption check here.
To learn more about non-repudiable versus repudiable reference here.
To learn more about non-repudiable signatures check here.
All of these documents have been moved from the Aries-RFC repository. To learn more about the broader aspects of DIDComm it would be best to check there.