Problem: The edit summary for this diff does display that a reference was added, but not which reference it is. References can be unreliable, spam links etc. so having them be easy to monitor is desirable.
Who would benefit: People who patrol Wikidata items for problematic edits, since the content of the diff is immediately displayed.
Proposed solution: Add the content of the reference to the edit summary; in this case it would be "Added reference (imported from:English Wikipedia) to claim: mountain range (P4552): Andes (Q5456)"
More comments: I hope that this isn't too late. This feature would be useful as well if it displayed in crosswiki watchlists. There may be length issues when the reference is long.