http://sparrowa7io5pz6ud3ehqzosvepbxbxt2zphmkjsylp2zgxooko23pqd.onion/docs/connect-node.html
Secondly, if you want to reverse this, you will need to start your full blockchain sync from the beginning again. Transaction Index If you are not using a pruned node, and you have a little extra disk space, you can add the transaction index in Bitcoin Core.
This enables certain features in Sparrow that are normally only available with an Electrum server, like looking up the inputs on transactions.