Specification
Specification covers the design of the various cryptographic constructs used in Bitwarden, and explains the rationale behind them. This is section is not meant for consumers of the APIs, but for developers working on the cryptography and for security researches verifying the designs.
Cose
Most new constructions and primitives are encoded in Cose objects. Reading the COSE standard is helpful to understand other parts of the specification. There are objects that are not yet transitioned.