Three steps to a cleaner session.
Install
Drag the .crx file into chrome://extensions with Developer Mode on. Then run install.bat to register the native messaging host — this is what lets Ctrl+X write your backup JSON to disk.
Save
Press Ctrl+X anywhere to save the current window and clear its RAM. Or click the extension icon, or open the sidebar panel — all three routes do the same thing.
Restore
Open Collections in the sidebar. Click any saved window to restore all its tabs at once. Choose whether to open in a new window or your current one.
What happens under the hood
When you press Ctrl+X, the extension captures the current window's tab URLs and metadata using the Chrome Tabs API, then writes the data into chrome.storage.local. Simultaneously, a message is sent to the native messaging host (a small Python script registered via install.bat), which writes an identical copy to umbrella-backup.json on your local disk. The browser window is then closed, which signals Chrome to reclaim the RAM those tabs were using.
No network request is made at any point. No data is ever transmitted off your machine. The native host process starts and stops with each save — it does not run in the background.
Everything Ctrl+X stores lives in chrome.storage.local and umbrella-backup.json on your machine. Read the full privacy policy →