System properties (stored in the sys_properties table) can be accessed in order to determine the behavior, or expected behavior, or all manner of functionality in ServiceNow. You can even create your own custom properties to control how custom functionality should behave.

The getProperty() method of the GlideSystem (gs) API accepts one mandatory argument, and one optional one: respectively, the property name, and a default value to return if the property is not found. It returns the value contained within the property or, as you might expect, the value of the second argument if the property is not found. If no second argument is specified and the property is not found, it returns null.