Action
The attribute data type of 'action' represents a string that can be used as an action; under the hood, Tinderbox caches the compiled action so it does not have to constantly re-parse the same expression. Thus these attributes should contain a string [sic] of valid Tinderbox action code.
Some pre-existing system attributes, such as OnAdd and Rule have been re-classed from 'string' to 'action' type.
This data type is not available for user attributes. Use 'string' instead.
The default value is an empty string.
Sorting order
As for String Data Type.
Action-type Attributes