how to check hidden parameter in oracle

select a.ksppinm name,
b.ksppstvl value,
b.ksppstdf deflt,
decode(a.ksppity, 1,
'boolean', 2,
'string', 3,
'number', 4,
'file', a.ksppity) type,
a.ksppdesc description
from
sys.x$ksppi a, sys.x$ksppcv b
where a.indx = b.indx
and a.ksppinm like '%replace_virtual%'
order by name;