Last modified: 2013-05-08 19:15:38 UTC
While the GUI versions for RecentChanges and Watchlist provide information about whether a change is flagged or not, these data seem to be missing in API. For action=query&prop=revisions FR provides a new value "flagged" for rvprop, which adds the desired information. This would be useful for list=watchlist and list=recentchanges, too.
For the moment you can use the watchlist as generator and than prop=flagged or prop=revisions&rvprop=flagged, but than other information from the watchlist are lost, but generator and list can be used both in one query.