ProtonMailCounter

Unofficial Proton Mail counter extension for chrome, refreshes the count every 15 minutes.

Extension launches pinned proton tab for 5 seconds in background to get the unread count, this allows to get the unread count without any credentials needed for the extension itself.

ProtonMail
https://mail.proton.me/

Source code is available at
https://github.com/KristianKalm/ProtonMailCounter