It turns out the Microsoft codename for that wave of deliverables is "Threshold."
A couple of my contacts have confirmed that Microsoft Executive Vice President Terry Myerson recently mentioned the Threshold codename in an internal email about plans for his unified operating-system engineering group.
If all goes according to early plans, Threshold will include updates to all three OS platforms (Xbox One, Windows and Windows Phone) that will advance them in a way to share even more common elements.
But Threshold will add another level of commonality across Microsoft's various Windows-based platforms, sources said. With the Threshold wave, Microsoft plans to support the same core set of "high value activities" across platforms. These high-value activities include expression/documents (Office, and the coming "Remix" digital storytelling app, I'd think); decision making/task completion (Bing, I'd assume); IT management (Intune and Workplace Join, perhaps?) and "serious fun."
Before Microsoft gets to Threshold, the company is on track to deliver an update to Windows 8.1 (known as Windows 8.1 Update 1) around the same time that it delivers Windows Phone "Blue" (Windows Phone 8.1). That's supposedly happening in the spring 2014/Q2 2014 timeframe, from what my sources have said.
I've asked Microsoft officials if they'd confirm any of this information about Threshold. No word back so far.
Update: A Microsoft spokesperson said the company had no comment on "rumors and speculation."