Windows Update Agent 7.6.7600.320

To everyone concerned about this, the "plumbing' has to update itself in order to maintain a healthy system.

In the background the WU engine itself HAS to update -  think of it like a heart beating that is keeping your blood flowing.  If it doesn't maintain itself, your computer system will not function.  Unless you turn updates completely off - any setting that has the updates merely checking will also ensure that this WU "engine" is functional. 

This is known, expected, documented and has occurred many times before.

http://blogs.technet.com/b/mu/archive/2014/06/24/upcoming-update-for-windows-update-client.aspx

When you first started your computer and agreed to the Windows TOC, you gave Microsoft explicit permission to automatically install Windows Update "infrastructure" updates - independent of your Automatic Updates settings. [But nobody bothers to read the TOC, do they?]

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Anytime Windows Update (or Automatic Updates) is turned ON, either set to automatically install updates or notify to download/install updates, Windows Update will take care of updating itself [i.e., Windows Update Agent].

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Source: http://blogs.technet.com/b/mu/archive/2014/06/24/upcoming-update-for-windows-update-client.aspx

The following expanded explanation is a tad outdated but still pertinent today:

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How Windows Update Keeps Itself Up-to-Date

Occasionally, we must update the infrastructure of Windows Update in order to ensure a high level of service quality, reliability, and operation.  As part of this process, we update both the back-end infrastructure that supports the service as well as the client side code (i.e. the Windows Update agent, or client).

So what are we doing this time? Well, this particular update won’t really change the way the client looks or feels to you, but you may notice some improvements in the length of time it takes Windows Update to scan for updates and how quickly you’ll receive signature updates...

What does this mean for you?

Anytime the Windows Update agent is turned on, Windows Update will take care of updating itself[i.e., Windows Update Agent].  Windows Update is considered “on” when anything other than “Never check for updates” or “Turn off Automatic Updates” is selected. What this means is that if you’ve selected “install updates automatically,” the update to the Windows Update client will install automatically.  You may also notice that Windows Update will also automatically download and install updates necessary for the Windows Update client to function properly[even]if you’ve chosen a different setting... [e.g., Notify but don't download & install; Download but don't install].  This is done in order to ensure that a system will continue to notify the user about available updates.  [emphasis mine]

The Windows Update client does not download or install infrastructure updates if the user has selected...“Never check for updates...”[emphasis mine] 

Windows Update has been keeping itself up-to-date this way for many years, and while these infrastructure updates are important to maintain the quality of the Windows Update service, they aren’t that frequent (they usually occur about once a year).

Why does Windows Update need to self update?

You may be wondering why this process is different from other updates you’ve come to expect from Windows Update.  The reason Windows Update issues infrastructure updates in this way is to ensure that users are able to successfully check for updates and/or receive expected notifications.  If Windows Update wasn’t able to do this, it may cause some users to believe that they have all of the latest security updates even though there was no installation and/or notifications of updates. To avoid a false sense of security, the Windows Update client automatically checks for and installs any available infrastructure updates anytime a system uses the Windows Update service, independent of the settings for how it handles updates...

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Source: http://blogs.technet.com/b/mu/archive/2008/07/03/upcoming-update-to-windows-update.aspx

I just spoke to a Microsoft support rep.  He is aware of the update (it a Microsoft update) but could not provide any worthwhile details or explain why it is being forced (overriding the Windows Update settings) on your computer or other PCs.. He will research the issue and Email me, lets hope he has worth reading.

J W Stuart: http://www.pagestart.com

Just a thought. Doesn't KB2887535 contradict your opening statement ***There is no stand-alone Windows Update Agent available to download.***in your previous post. It might be worth adding a late edit there.