Sync stores data on this site's own backend (Netlify Blobs). Your code is the only
key — anyone with it can read or write your data, so keep it private.
Heads-up: sync only works when the app is hosted on Netlify
(it uses a backend function at /.netlify/functions/sync). Open the
app from your Netlify URL to use sync.
This device is syncing. To set up sync on another device, open the app there,
click Sync, and paste this code.
…
Local data stays. Other devices keep syncing among themselves.