Microsoft pushed a small update to Windows 10 PCs this morning. Dubbed KB3140741, the update goes by pretty quickly and doesn't require a reboot.
This update makes stability improvements for Windows 10 Version 1511 servicing stack.
If you are installing a servicing stack update package for the first time, the package for the x86 version is 5 MB and the package for the x64 version is 11 MB.
The update isn't yet listed on Microsoft's Windows 10 update history page. We'll be sure to check back if Microsoft's provides any sort of changelog for KB3140741.