Gnome Email Notifications
Utilizes Gnome Online Accounts to login to Gmail/Outlook and check your incoming email
Install gnome-shell version 3.22 or later.
Sign in with your Google and/or Microsoft account in Gnome Online Accounts settings.
Either install from https://extensions.gnome.org/extension/1230/gmail-message-tray/
OR
run git clone --depth 1 https://github.com/shumingch/gnome-email-notifications ~/.local/share/gnome-shell/extensions/[email protected]
journalctl | grep "Gnome Email Notification"
into terminal.