Bookmark Preview by andytw366

Once you have a few hundred bookmarks, the bookmark menu is just a wall of text. This extension turns it into something you can actually look at: bookmarks as visual previews, plus a password-encrypted vault whose entrance is hidden.

■ Visual previews

A sidebar that lists bookmarks with thumbnails, in three densities (card / row / text-only). When you want to scan dozens of covers at once, "Full page" lays them out as a grid across the whole window.

Previews prefer the page's own cover art — comic and book covers, video thumbnails — and fall back to a screenshot only when there isn't one. For content pages a cover represents the bookmark far better than a screenshot, which usually just shows a navigation bar. Covers keep their original aspect ratio instead of being cropped.

The heuristics never look at the domain, so there is no site list to maintain and no per-site tweaking. Automatic detection can't be right everywhere, so there is a direct override: right-click any image on any page and choose "Use as this bookmark's preview".

■ The vault

Create an encrypted bookmark space behind a master password. Bookmarks moved into it disappear from Firefox's bookmark manager, toolbar and menu; they are only visible after you unlock. Their preview images are encrypted too (AES-256-GCM). Whole folders can be moved in with their structure intact.

The entrance is hidden by default: the sidebar shows no trace of it. You type a trigger string of your choosing into the search box to bring up the password screen. It re-locks automatically a configurable number of minutes after you last touched the vault, when you walk away from the machine, or when you close the sidebar.

A forgotten master password cannot be recovered, so you get a recovery key when you create the vault, and you can export an encrypted backup file. You can also opt in to putting an encrypted copy in Firefox Sync to use it on your own other devices — what leaves the device is ciphertext, unreadable to the sync server.

■ Privacy

Everything stays on your device (IndexedDB and storage.local). No server, no account, no telemetry of any kind. Data leaves your device only if you opt into sync, and then only as encrypted bytes.

■ Keyboard

The whole flow works without a mouse: arrow keys to move between bookmarks, Enter to open, Right Arrow to enter a folder, Backspace to go up, Menu key or Shift+F10 for the context menu.

■ Permissions

"Access your data for all websites" and "browsing history" are both optional — the extension works without them:
・All websites — needed to read the rendered page when generating previews. Without it you get colour cards keyed to the domain.
・Browsing history — when you move a bookmark into the vault, this deletes that URL from history (otherwise the address bar still autocompletes it). Deletion only; nothing is read or transmitted.