Script for finding undocumented parameters

Code:
SELECT   a.ksppinm parameter
        ,a.ksppdesc description
        ,b.ksppstvl session_value
        ,c.ksppstvl instance_value
    FROM x$ksppi a
        ,x$ksppcv b
        ,x$ksppsv c
   WHERE a.indx = b.indx AND a.indx = c.indx AND SUBSTR (a.ksppinm
                                                        ,1
                                                        ,1
                                                        ) = '_'
ORDER BY a.ksppinm
/
HTH