Stash stores every bookmark encrypted in chrome.storage.local. The
password you set is never persisted — it derives the encryption key on
each unlock via PBKDF2. Screenshots are only taken of pages you
explicitly bookmark, and they live inside the same encrypted vault. The
extension makes no network requests.
The "Read your data on all websites" permission is required by Chrome
to capture screenshot thumbnails of the page you bookmark — Stash does
not use it for anything else.
Source code: https://github.com/hun1138/private-bookmark
License: MIT