Open Other Org
This feature allows you to open the current page or a Saved Tab in another org, if you know its link and have valid credentials for it.
To get to the Modal in the picture above, you'll need to use the Context Menu (right-clicking) either on the current page (to open it somewhere else) or on a Saved Tab (to open the Saved Tab somewhere else).
Once you fill in the other org name, click on the blue "Continue" button; a prompt will ask you to confirm the link and after you confirm, a new tab will be created with the page you chose in the org you specified.
The URL input field has a trick up its sleeve: it follows the same logic as the Tab's org property! Try pasting a full URL instead of writing the ORG name!