For wiki page I can write a short diff ( https://meta.wikimedia.org/wiki/Help:Diff#Diff_link )
https://www.mediawiki.org/w/index.php?title=Extension:Wikibase_Repository/fr&curid=215365&diff=1512900&oldid=1512898
--> [[mw:Special:Diff/1512898/1512900]] [[mw:Special:Diff/1512900]]
Flow should also support the work with a short link
https://www.mediawiki.org/w/index.php?title=Topic:Sep7rxhmmbo71xks&action=compare-post-revisions&topic_newRevision=sepexvi5gfejfmhr
--> [[mw:Special:Diff/sepexvi5gfejfmhr]] - it does not work