If for whatever reason, a Sparrow multi-sig wallet user starts to use a new desktop or laptop. User reinstalls Sparrow, Electrum or such interface on new machine. In order to migrate a previously established multi-sig to the new instance of sparrow/electrum, etc, is it possible to rebuild the same wallet with just the seed phrases of the participating cold signers? Or is it required to reestablish the wallet using the wallet setup file using the pubs? Additionally, is the output wallet descriptor file enough to reestablish the multi-sig wallet? What I'm getting at is, just how important is it to have the wallet setup file or the output descriptor file backed up. Thank you.
If you are asking of maybe the wallet file of the multisig wallet is less important or if you lost it you will be able go back up your wallet I will say what you mostly need is the seed phrase of each co-signers and also the master public key of every co-signer.
Example is if you create a 2-of-3 mult sig wallet you need.
1. The wallet 1 seed, master public key 2 and master public key 3 for the first wallet recovery.
2. For wallet two you need wallet seed 2, master public key 1 and master public key 3 for the second wallet recovery.
3. The last wallet recovery you need wallet seed 3, master public key 1 and master public key 2 for the last wallet recovery
What you need else again is the wallet setup script which in this case is 2-of-3, if you mistake it like you use a script of 3-of-3 you can be able to recover the multi sig wallet. So the master public keys of other co-signers are as important as the seed phrase of each wallet. With this there is no need trying to back up any file