SELECT extractValue(value(h),'.') AS hint
  FROM sys.sqlobj$data od, sys.sqlobj$ so,
  table(xmlsequence(extract(xmltype(od.comp_data),'/outline_data/hint'))) h
  WHERE so.name = 'opt_estimate'
  AND so.signature = od.signature
  AND so.category = od.category
  AND so.obj_type = od.obj_type
  AND so.plan_id = od.plan_id;
  
  

Source: https://antognini.ch/2008/08/sql-profiles-in-data-dictionary/