Locations are mainly something the dspec system just stores and retrieves.
locations are used to describe definitions located as subforms of other definitions.
locations are usually not explicitly specified, but arise as a result of having two nested definitions, both of which use the def and location macros to handle the name and location info.
The types of locations and their meanings are:
A definition existed in the file named or an editor buffer with that name.
A definition was executed interactively in the listener or an editor buffer not associated with a file.
A definition was found in the image (these are entered when a location query does not find any information already in the database).
A definition for a part was recorded, but no information exists for the aggregate.
LispWorks User Guide and Reference Manual - 21 Dec 2011