Judge once more screening foreign fighter's record collection (8)
I believe the answer is:
registry
'record collection' is the definition.
'registry' can be an answer for 'record' (I have seen 'official record' mean 'registry' so perhaps 'record' could also mean 'registry'). I'm not sure about the 'collection' bit.
'judge once more screening foreign fighter's' is the wordplay.
'judge once more' becomes 'retry' ('try' is an answer for 'judge' so perhaps 'retry' is OK for 'judge once more').
'screening' indicates putting letters inside (inserted letters are covered or screened by others).
'foreign fighter's' becomes 'gis' (I can't explain this - if you can you should believe this answer much more).
'retry' going around 'gis' is 'REGISTRY'.
Can you help me to learn more?
(Other definitions for registry that I've seen before include "Place where written documents or records are kept" , "record-holder" , "Place of record" , "Office where records are kept" , "Place to keep records" .)