Some call extensions the bread and butter of a browser. While I'd say that other factors play a role here as well, it is undeniable that extensions can improve the usability of a browser and browsing the Internet significantly.
The popularity of extensions on the other hand has brought with it abuse of said system, usually for monetization or tracking purposes.
Companies like Mozilla or Google have started to improve the security of their web browsers in regards to extension installations to protect the user base from malicious or ad-related extensions.
Google has been very busy in the past two years. It all began with the blocking of direct extension installations from third-party websites (read non-Chrome Web Store), went on with the blocking of silent extension installations, and the scanning of all third-party extension installations for malware.
That was not the end of it though. Google announced late last year that it would prevent the installation of third-party extensions in Chrome Stable and Chrome Beta versions on Windows, which basically means that users who run these browsers can only install extensions from the official Chrome Web Store and no other location.
The most recent change landed last week when Google added extension permission confirmations to all installations.
That's still not all though. The company has added a new feature to the Canary version of Chrome for Windows that will display web store information for every externally installed extension.
The web store information that get displayed include the rating of the extension, the users, information that it was installed by another program on the computer, and buttons to view details about it, or remove it from the browser again.
It is interesting to note that this falls in line with last November's announcement that all Chrome extensions for Beta or Stable users had to be uploaded to the store. The deadline for that was January 2014 which coincides with the new feature that just got added to Chrome Canary.
It is not clear how the policy affects extensions that do not comply with Chrome Web Store policy. Some video downloaders and extensions that bypass country restrictions are for example not offered on the store because of those policies.
At the very least, it is a side effect that gives Google more control over which extensions are available for Chrome, and which are not.