The Purpose of $tw.mws.store.getBagRecentTiddlers(bag_name, greater_than_tiddler_id, limit)
is to be able to poll the MWS tiddler database for new and updated tiddlers.
These are the current tiddlers in 'bag-alpha':
$tw.mws.store.getBagTiddlers('bag-alpha')
[
{ title: '$:/SiteTitle', tiddler_id: 18943 },
{ title: 'In the bag', tiddler_id: 13264 },