diff --git a/repository/Grafoscopio/FossilRepo.class.st b/repository/Grafoscopio/FossilRepo.class.st
index 4c81d13..8c9bcf0 100644
--- a/repository/Grafoscopio/FossilRepo.class.st
+++ b/repository/Grafoscopio/FossilRepo.class.st
@@ -12,6 +12,11 @@ Class {
 	#category : #'Grafoscopio-Model'
 }
 
+{ #category : #'as yet unclassified' }
+FossilRepo >> hashNumberFor: aFileName [
+	^ (((self jsonDataFor: aFileName)  at: 'payload') at: 'checkins') first at: 'uuid'
+]
+
 { #category : #'as yet unclassified' }
 FossilRepo >> jsonDataFor: aFileName [
 	^ NeoJSONReader fromString: (self jsonStringFor: aFileName)