The application's code hints at more upcoming features, too. There's a reference to "secret conversations" tool, but unfortunately there's little explanation. Sure, it could mean encrypted chats like WhatsApp and other apps offer, but it could also be a way to hide threads within Messenger. Details are scarce on that one for now, so we'll have to wait and see if more info creeps out or for a formal announcement.
Facebook seemingly wants Messenger to play a bigger role in how you go about your day as well. The Information also viewed source code that discusses syncing calendars, sharing quotes from articles and beaming News Feed-style status updates to only a select few friends. In terms of your calendar, the code references being able to add events and "organize your day."
Since the app's code is the source for all of this info, we could be waiting a while before Facebook makes anything official. However, it's certainly interesting that the company has some big plans in the works for Messenger, including a way to handle payments that's more than just sending money to a friend. That money-sending feature was tipped in source code several months before it arrived as well, so perhaps we'll get some official word soon enough. We've reached out to the social network on the matter and will update this post when/if we hear back.