Proton Switch by Pragadesh B S

Proton Switch is a open source Firefox extension that simplifies the process of switching between multiple ProtonMail accounts. With Proton Switch, you can quickly and easily access and switch between your ProtonMail accounts without having to go to the official ProtonMail switch web page every time. This extension provides a more efficient and streamlined process for managing multiple ProtonMail accounts.

View the source code on GitHub