An Enumeration actually is meant for named constants. (0 = “Orange”, 1 = “Apple”, 2 = “Banana”, …) . Blender stores integers internally for enumeration props and saves them to the blend.
The name, description and icon are passed for the GUI.
You can access the items via
#YourAddonPreferences subtype of bpy.types.AddonPreferences and has been registered
items = bpy.types.YourAddonPreferences.render_type[1]['items']
Put your delimited list elements in the first field and then you can access them directly. The second field will appear in the AddOns UI preferences panel. The 3rd value is not accessible at this time (AFAIK).
It depends of where you need to access them. If is in the preferences file you can access the item array if you just define in a scope where the updatePrefrences function can reach it.
You can also access them through RNA Type etc. In the updatePreferences function is is a update= callback you can do this access it
print(self.rna_type.render_type[1]['items'])
also note that you don’t have the operator he is showing you as an example.