How Eddystone URL Works
Eddystone URL relies on a beacon sending a web address (1) that is picked up by either the Android OS or the Physical Web App on iOS or Android. These contact (2) the Google Physical Web Proxy to get an icon and description. If the Google Physical Web Proxy already has these details and they are not too old and the site hasn't been blocked, it sends the cached details back. If it doesn't have these details yet or they are too old then the Google Physical Web Proxy contacts (3b) the destination web site to get the latest web site description and icon. It might have to first get (3a) the full web address from a URL shortener.
The Android OS or the Physical Web App show a notification with the title and icon. When the user taps on the icon, the user is sent (4b) to the destination web site. If a URL shortener has been used then the web browser will first have to get (4a) the full web address.