Variables declare a way of binding input data, usually fact items, to a name that can be referenced by variable name, such as from within an assertion or formula expression. Variables that bind to input fact items are fact variables and use filters to declare what they can bind to in the input. General variables are used for intermediate expression results and other kinds of processing.
A general variable provides the Boolean property Bind As Sequence as an icon. The value of the property Select is an XPath expression.
A fact variable provides the Boolean properties Bind As Sequence, Nils, and Matches as icons. The value of the property Fallback Value is an XPath expression.