Screenshots of Windows 8.1 build 9385 surfaced on the internet today, hinting at the possibility of the build leaking itself in the coming days. As well as the desktop image, a screenshot of what appears to be a user downloading the ISO has also emerged.
Builds of Windows 8.1 (codenamed "Blue") have become common in recent weeks. In the previous few weeks, builds of Windows 8.1 have leaked in intervals of five: 9364, 9369, 9374. Build 9385 breaks that trend, although if it is similar to the previous leaks will likely include numerous bug fixes and further control panel options.
Given that news the Start button would be returning in Windows 8.1 surfaced over a week ago, we may see evidence of this in code in build 9385, though the button doesn't appear in the leaked screenshots, indicating it's not yet enabled by default (and possibly not in the build at all).
PCBeta reports that the build was being distributed to Partners on the Microsoft Partner Network just a week ago. The build was compiled on April 15, although thus far it is unclear what exactly the build includes.