Delivery model. Authenticity.
- Install web extension manually verifying its authenticity and security using corresponding scanners and utilities
- Get web extension as preinstalled with the corporate version of the browser.
NOTE that in a web application case, the user doesn’t have control over the webserver that is providing the web application, any web service provider can potentially provide a malicious version that could compromise the encryption.
It's valid for webmail encryption services like ProtonMail, Tutanota, ...
"Each component of the extension runs in a different process. The extension core and the native binary each receive dedicated processes. Content scripts run in the same process as their associated web pages.