Query Database Hidden Parameters

select nam.ksppinm name, val.KSPPSTVL, nam.ksppdesc description
from x$ksppi nam, x$ksppsv val
where nam.indx = val.indx AND
nam.ksppinm = '<name of hidden parameter>'
order By 1
/

Sample Output:

 select nam.ksppinm name, val.KSPPSTVL, nam.ksppdesc description
 from x$ksppi nam, x$ksppsv val
 where nam.indx = val.indx
 AND
 nam.ksppinm = '_awr_restrict_mode'
 order By 1;

NAME
--------------------------------------------------------------------------------
KSPPSTVL
--------------------------------------------------------------------------------
DESCRIPTION
--------------------------------------------------------------------------------
_awr_restrict_mode
FALSE
AWR Restrict Mode