Good point. This is also the same for KeePassXC where the browser extension works by communicating with the main app process. The extension itself doesn't store

Good point. This is also the same for KeePassXC where the browser extension works by communicating with the main app process. The extension itself doesn't store the passwords. And KeePassXC is open source and does not require cloud storage. So you can build from source and do not need to rely on any claims from the vendor on how the data is securely stored.