Source : https://denysdovhan.com/inboxer/
Download :
https://www.qnapclub.eu/fr/qpkg/698
About :
It's built on top of Inbox by Gmail web-version, has pleasant UI and supports useful keyboard shortcuts.
Features
Familiar Inbox by Gmail interface
Cross-platform (macOS/Linux/Windows)
Useful Keyboard shortcuts
Multiple accounts
Optional Always on Top
Auto-updates to the latest version
Desktop notifications
TODO: Dark theme
TODO: Custom text size
TODO: Ability to use as default mail client