Determining if an extension was installed through Chrome Web Store or not?

[Karl Reid]

Hi, I noticed that in chrome://extensions you can see a "Not from Chrome Web Store" message under extensions that were installed through, e.g. drag and drop into the extensions page. Screenshot of what I am talking about : 

 I was wondering if there is any way of getting that information from an extension API? I have played with the chrome.extensions.management API, but the only information that gives is the installType field, which is 'normal' for both Web Store and drag and drop installs. - https://developer.chrome.com/extensions/management#type-ExtensionInfo

Am I missing something, or will we just have to wait for an update to the management API?

Thanks for any info!