What do desktop notifications do?
Desktop notifications create a popup message each time an inbound call is received. Popup messages provide both a visual and audio notification of an inbound call and appear even when the browser is minimized.
What is the enable desktop notification?
If you're using either Chrome, Firefox, or Safari as your browser, you can enable desktop notifications. While enabled, a notification will appear whenever a new email message arrives in your inbox as long as you have Gmail open in a browser tab.