Is there a specific email body/template when using the "Global Notifications" email address? (4258863)

Is there a specific email body/template when using the "Global Notifications" email address? 

If yes, can that be changed?

There is not specific email body/template. The email body is the one which is configured in the rule. 

The "Global Notifications" email address is the default email address, if an email action is configured but no email recipient is defined in the rule itself. This works only for Core rules, other cartridges have their own default email address variable for example "Database Notifications" or "Operating System Notifications".