CLCS

:WILD as a Component Value

If :wild is the value of a pathname component, that component is considered to be a wildcard, which matches anything.

A conforming program must be prepared to encounter a value of :wild as the value of any pathname component, or as an element of a list that is the value of the directory component.

When constructing a pathname, a conforming program may use :wild as the value of any or all of the directory, name, type, or version component, but must not use :wild as the value of the host, or device component.

If :wild is used as the value of the directory component in the construction of a pathname, the effect is equivalent to specifying the list (:absolute :wild-inferiors), or the same as (:absolute :wild) in a file system that does not support :wild-inferiors.