How to find out used database features?

Set feedback off
Set linesize 122
Col name             format a45     heading "Feature"
Col version          format a10     heading "Version"
Col detected_usages  format 999,990 heading "Detected|usages"
Col currently_used   format a06     heading "Curr.|used?"
Col first_usage_date format a10     heading "First use"
Col last_usage_date  format a10     heading "Last use"
Col nop noprint
Break on nop skip 1 on name
Select decode(detected_usages,0,2,1) nop,
       name, version, detected_usages, currently_used,
       to_char(first_usage_date,'DD/MM/YYYY') first_usage_date,
       to_char(last_usage_date,'DD/MM/YYYY') last_usage_date
from dba_feature_usage_statistics
order by nop, 1, 2