KB2199355 (aka Windows 8.1 Update 1) contains several files, including KB2199355.
Here's summary for you... (Thanks to Michael Niehaus of Microsoft)
The original MSDN download contained KB2919355, KB2932046, KB2937592, KB2938439, and KB2949621.
The first version of the update published to WU contained KB2919355, with child updates KB2932046, KB2937592, KB2938439, and KB2934018 (which is a roll-up containing KB2949621).
The second version of the update published to WU, which is the only one published to WSUS, added KB2959977 to the above list but made no other changes.
The 2.6mb file just released under the KB2919355 moniker is KB2959977. Here is a link to KB document:
»
support.microsoft.com/kb/2959977