@david @pojntfx I was mostly thinking of NLWallet, which is actually government backed/owned. As far as I know it’s ZKP, and it’s even open-ish (not GPL, but at least source-available). You can build it from source yourself.
But I’m not as knowledgeable on the matter as @pojntfx, so I could absolutely be missing something here on the implementation of zero knowledge here.
See their GitHub page here: https://github.com/MinBZK/nl-wallet