Besides the update for Insiders on Windows 10 PC, there appear to be a two other updates going for some Windows users. One is a cumulative update likely tied to today's earlier announcement regarding updates to Windows 10, and the other is a general update for Windows 10 for x64-based systems.

One update is for KB3105210 and patches Internet Explorer and Microsoft Edge for security reasons and KB3106932 is a 'Compatibility update for upgrading to Windows 10' that "makes improvements to ease the upgrade experience to Windows 10". That latter one is likely tied to Terry Myerson's earlier blog post regarding their new policy on updating to Windows 10 and streamlining the process.

You can find more details about both updates through their knowledge base articles: