WEB BROWSER Chromium along with its Google cousins Chrome and Chrome OS will block local extensions.
The previously announced move will begin starting with Chrome 33 Beta, with extensions not sourced from the Chrome Store being marked with "suspicious extension blocked" and disabled.
The reason for the decision is attributed to concerns about the dominant Windows PC operating system, which does not have sandbox capabilities and therefore is particularly vulnerable to embedded malicious code.
Developers are advised to migrate their extensions to the Chrome Store immediately. A FAQ on the Chromium Project website explains options for restricting specialist extensions for closed user groups.
For testing purposes, the rule will not apply to developers using Chrome in Developer Mode, which could lead to it being used as an equivalent of Android "rooting", with local extensions being available with extended functionality but at end users' risk.
Also excluded will be Chrome browsers running in an enterprise environment, where bespoke extensions for internal business use might be necessary.
Google said that there will be no visible change for the end user - browsers will automatically update the extension to the Google Play store version and it will be updated from there from then on.
Chrome engineering director Eric Kay said at the time of the original announcement, "Protecting our users is a key priority, and we believe this change will help those whose browser has been compromised by unwanted extensions."
Chrome Beta 33 is already live, with a stable version expected towards the end of the month. µ