The Org Organizer saves your orgs to your account so they sync across browsers. Credentials are encrypted at rest and only ever decrypted inside the login route.
If you juggle a Production org, a few sandboxes, and a couple of Dev orgs, signing in to the right one is half the friction of switching contexts. The Org Organizer lets you bookmark every org you use, group them under Production / Sandbox / Dev Org (or any custom category you make), and click a thumbnail to land inside that org already authenticated. OAuth is the recommended path - you authorize a Connected App once per org and we mint a fresh session every click, so the connection respects your MFA settings and is revocable from Salesforce Setup.
Each org you add lives as a row in your account. For OAuth orgs we store an encrypted refresh token; on click we use it to mint a short-lived access token and redirect you through Salesforce's frontdoor.jsp SSO endpoint into your home page. For username/password orgs we encrypt the password and security token at rest, do a SOAP login on click, and use the same frontdoor endpoint. You can also override the login domain per org if you use a my-domain (acme.my.salesforce.com) instead of the generic login or test endpoints.