Just a small quibble, if you're typing in the textarea the website or any other extensions you have in your browser could spy on the plaintext as it is being ty

Just a small quibble, if you're typing in the textarea the website or any other extensions you have in your browser could spy on the plaintext as it is being typed. A secure browser extension would have to call an external program, let you type and encrypt your message in there, and then deposit the encrypted message back into the textarea.