This is a browser extension for Microsoft Edge and Google Chrome. When you click the button, it merges tabs in all windows into a single window. It essentially provides the same feature as the Merge All Windows feature in Safari. This is handy if you open many websites in many windows and you want to consolidate your workspaces.
Unlike existing extensions, this one requires no special permissions and does not require your browser history.
Within Microsoft Edge, navigate to edge://extensions.
Then enable 'Developer mode' in the bottom left.
Go to the Extensions page of Edge. When installing this extension for the first time, click the Load unpacked button. Then select the directory containing a copy of these files.