- MultiSigs are made up of several keys (2FA's are made up of 3)
- You need to get all the individual pieces (Electrum will only give you 1, by clicking "export private key"). This requires digging around in wallet files and using various tools to convert the redeem script into individual addresses and using xprvs to find the private keys for those individual addresses
- Once you have all the pieces, you can use them to manually create a "raw" transaction.
- You then sign the raw transaction using the individual pieces that you extracted and you can broadcast the message.