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 unsure of 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' means one lot of letters goes inside another (inserted letters are covered or screened by others).
'foreign fighter's' becomes 'gis' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'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" .)