Cooperation with other projects

[ChristopherA]

In addition to the existing people assembled from Blockchain Commons, BaseZero, and Unchained Capital and some bitcoin-core folk, there are a number of other projects we should coordinate with. Please add them to this issue.

[ChristopherA]

Specter:
https://github.com/cryptoadvance/specter-diy/
https://github.com/cryptoadvance/specter-desktop/

[stepansnigirev]

Working with airgapped signers over QR codes:
https://github.com/spesmilo/electrum (electrum transaction format)
https://github.com/BlueWallet/BlueWallet (psbt)