Ok so I have an Intent to Implement: Wallet Attached Storage.
But... what is a Wallet?
https://en.wikipedia.org/wiki/Digital_wallet has a good definition:
software program that allows one party to make electronic transactions with another party
Frankly a digital 'wallet' to me is nothing in particular. As far as I can tell, the term is thrown around pretty loosely to a broad category of apps, web services, open source projects, for-profit companies, continent-scale digital public infrastructure components, etc. The features in your average ethereum or bitcoin wallet are really different than what I'd expect in EU Digital Identity Wallets.
But while there is a lot of variation, I'd say the one thing that is constant is that a wallet enables the ability to create proofs for at least one verification method (e.g. a crypto key). These proofs enable the verification of authenticity of well-defined structures of the aforementioned 'electronic transactions'.
Basically when people say 'wallet' they tend to do so to convey that whatever the application does, it will have a subcomponent that stores some private keys, probably some other metadata e.g. nonces, credentials, and has the ability to use the private keys to create new digital signatures as proofs. The implication is that these proofs can be shared with others, loaded into other 'wallet' software and the proof 'verified' according to some well-defined rules. One example of how this can all come together is Verifiable Credential Data Integrity Proofs.
tl;dr:
A digital wallet is a program that creates proof.