Sometimes you may need to see Default subscriptions for any user or group as there may be cases where they might be receiving notification twice for a single work item update or build update

Step 1: Go to Organization Settings

Step 2: Click on Global Notifications

Step 3: Click on Subscribers

Step 4: Then search for the user or group as shown below

Step 5: You will be able to see the list of Global subscriptions as well as project subscriptions in Azure DevOps for the user or the group