Recovery Keys are kept off-device and are used to restore access to your Fuse wallet in case you lose one of the two primary keys.
When you first sign up for Fuse, add at least one Recovery Key to complete the onboarding process. You can have up to three recovery keys using multiple email addresses, Ledger, or any Solana wallet.
This means you can use your Phantom or Ledger wallet to recover your Fuse account. As long as you have one of your Recovery Keys, you can “vote” to regain access to the wallet by pairing the Recovery Key with your Device or 2FA Key.
Here's how to add or remove a Recovery Key
Click here for a guide on adding Recovery Key
Click here for a guide on removing an existing Recovery Key
Read this article for more information on Fuse's security.