Select > Install page as app (or "Create Shortcut" and check "Open as window").
Because the browser itself is portable, all your session data and the "app" interface stay within the portable browser's folder on your USB drive. Security Best Practices for Portable Users proton mail desktop app portable
: Avoids exposing your email activity to browser extensions or ad trackers that might be present in standard browsers like Chrome. Security Risk Select > Install page as app (or "Create
A portable app is a software application that can be run from a portable storage device, such as a USB drive, without requiring installation on the host computer. This allows you to carry your apps and data with you, using them on any computer without leaving a footprint. such as a USB drive