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Local crash recorder for tabs and groups. Native discard. Encrypted backup. No telemetry. Blackbox records the web tabs and tab groups you have open so you can restore a saved recovery seal after a crash or restart. It saves http and https tab addresses and titles, pinned state, window layout, and tab-group names, colors and collapsed state as a recovery seal on this computer. Restore opens the saved recovery seal in new windows and recreates its groups, without closing the tabs Chrome has already reopened. If most of your tabs disappear at once, Blackbox keeps the previous recovery seal for 10 minutes so a nearly empty session does not replace it. You can also choose any of the 20 most recent seals in Backup and settings. Blackbox can park idle tabs with Chrome's native tab discard, freeing page memory while each tab keeps its address. Parking runs when you click Park idle, or with the automatic seal if you turn that option on. For portable recovery, you can download an optional .bbx backup encrypted with a passphrase you choose. The file contains only encryption settings and ciphertext, and Blackbox never uploads it. Session contents are encrypted locally with AES-GCM. The device key is kept in Chrome's local extension storage so restore works without a passphrase, and seal names, times, counts, settings and the optional passphrase hint also stay readable there. Anyone with access to your Chrome profile may be able to read them. Blackbox has no account, server, analytics, telemetry or extension-initiated network requests. When you restore, Chrome loads the saved web addresses as usual. Blackbox restores a saved recovery seal. It does not guarantee recovery of your latest browser state: changes made in the last few seconds to about a minute before a crash may not be sealed, and only http and https tabs are recorded.
Nov 11, 2026
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