What are the search fields to find a hit from the known error libary?
Only Known Errors
Check only the checkbox of "known errros " in order to search for hits in the known error library
and both if you want to serach in both
Access Knowledge Managment > Configuration > Manage Knowledgbases (or just KM > Configuration> Knowledgebases in newer releases).
Search for then Known Error library.
The fields mapped to be indexed are outlined on the Field Defintions tab.
That's what i was looking for....