This could only be coincidence, however it appears as if Google is doing some prep work for the upcoming announcement and launch of Android 4.4 Kit Kat. Specifically, some public facing prep work. Reddit user JLishere has noticed that Google has been updating apps. Actually, updating quite a few of the core apps.
At present the updated app count is sitting at 16. The list includes Google Play Services, Gmail, Drive, Calendar, Earth, Translate, Chrome, Hangouts, Goggles, Play Magazines, Keep, Wallet, Blogger, Google+, Analytics and Fiber. Some of these apps, such as Google+ and Hangouts are likely due to the Morning with Google+ event we saw yesterday, but overall 16 apps in this short of a period does have it looking like something bigger is coming.
Unfortunately, this doesn't give a clear indication and as we mentioned, it could be nothing more than coincidence. Still between the rash of recent Nexus 5 inventory sightings, combined with the previous leaks and rumors, it does appear an announcement is coming -- and coming soon. The most recent chatter has Google unveiling everything on October 31 or November 1, though given the Kit Kat connection, a Halloween unveil would seem the more likely between the two dates.
On the flip side, the mass of press invites has yet to surface online. Those tend to come more than a day or two ahead of the scheduled event. In the meantime, we suspect the teasers are going to continue. To that point, the folks at Kit Kat dropped another last evening. Titled Android Animation -- Magic, this video is short and entertaining, but we would have preferred to see the wave of the candy wand to produce a Nexus 5 instead.