François Beaufort has updated his Extension Update Notifier browser extension for Google Chrome.
The updated version would now warn you about browser extensions that are installed without your approval.
Apparently, Google Chrome enable developers to activate a browser extension without even informing the user about it. This feature is mostly used by security software products like Avast Antivirus.
Chrome users have raised this issue on the Chromium Issues page. Check it out here. Star it to highlight it and leave a comment if you think this needs to be fixed!