lawks

It seems that ignorance abounds in this post's comments. People are apparently unaware that one can write an extension that has no more privileges than a normal web page, and unlike a page, the code cannot change on every load. Your idea is good. I'd recommend not using any minification or obfuscation in the extension, and keep it as brief as is possible, for maximum transparency.

In a parallel situation, I've always been wary of hosted password managers' web interfaces like those of Lastpass, 1Password, and even Bitwarden, because one has to accept the code served at every access is clean. Ultimately, one enters their master password/secret keys, as plain text, into a web page that's difficult to audit & unlikely to be, on every view. Whereas offline/client-side encryption outside the transmission medium is far more trustworthy (e.g. KeePass).

When was the last time you wrote an extension? Long gone are the days when they could run system commands, and permissions must be declared in the manifest or they cannot be used, so if they aren't in there, they're not being used.