describe displa lisp error?



GCL returns obscure error message:
------------------------
MAXIMA> (describe 'displa)

DISPLA - internal symbol in MAXIMA package
 property TRANSLATED:
   T
 property MACSYMA-MODULE:
   (RUNTIME)
-----------------------------------------------------------------------------
DISPLA 
[Function]
(not found "dir")
Maxima encountered a Lisp error:

 Error in PCL::PCL-DESCRIBE [or a callee]: Cannot open the file NIL.

Automatically continuing.
To reenable the Lisp debugger set *debugger-hook* to nil.

MAXIMA> (describe 'dir)

DIR - internal symbol in MAXIMA package(not found "dir")
Maxima encountered a Lisp error:

 Error in EVAL [or a callee]: Cannot open the file NIL.

Automatically continuing.
To reenable the Lisp debugger set *debugger-hook* to nil.
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Is this a feature of GCL , or a lack of code documentation?

Ted Woollett