This is added automatically to the child container of an exploded note. In order to allow customisation before first use, this prototype can be added to a document from this menu without first invoking an Explode operation.
Note that the prototype is capitalised deliberately. This ensures it is not matched by queries looking for, and acting on, the 'exploded notes' container that is generated by all 'Explode' operations.
This prototype's non-default customisations other than $IsPrototype, $Name, and intrinsic map features (height, width, etc.) are listed below.