Google’s journey to Chrome “Manifest V3″has been going on for four years, and if the company’s new timeline holds up, we’ll all be forced to move to it in 5 years. “Manifest V3″is a rather unintuitive name for Chrome. the next version of the Chrome Extension Platform. The update is controversial because it makes ad blockers less effective under the guise of protecting privacy and security, and Google just so happens to be the biggest ad company in the world.
The latest Google blog post details the new Manifest V3 migration schedule, which includes ending support for older extensions running on Manifest V2 and forcing everyone to migrate to the new platform. Beginning in January 2023 with Chrome version 112, Google “may experiment to disable support for Manifest V2 extensions in the Canary, Dev, and Beta channels.”Starting in June 2023 and Chrome 115, Google “may experiment to disable support for Manifest V2 extensions in all channels, including the stable channel.”Also, starting in June, the Chrome Web Store will no longer accept Manifest V2 extensions, and they will be hidden from view. In January 2024, Manifest V2 extensions will be completely removed from the store.
Google says Manifest V3 is “one of the most significant changes to the extension platform since its launch ten years ago.”The company claims that the more limited platform is meant to “improve security, privacy and productivity.”Privacy groups such as the Electronic Frontier Foundation (EFF) dispute this description and say that if Google really cared about the security of the extension store, it could just control the store more actively using real people instead of limiting what all extensions can do..
The main killer of ad unit extensions has to do with changes to the way network request modifications work. Google says that “instead of intercepting the request and modifying it procedurally, the extension asks Chrome to evaluate and modify requests on its behalf.”Chrome’s built-in solution forces ad blockers and privacy extensions to use a primitive solution in the form of a raw list of blocked URLs, rather than the dynamic filtering rules implemented by something like uBlock Origin. This list of URLs is limited to 30,000 entries, while a typical ad unit extension can contain over 300,000 rules.
EFF found holes in most of Google’s justifications for the Manifest V3 changes, stating that malicious extensions are mainly interested in stealing data and that Manifest V3 only prevents extensions from locking data rather than verifying it, so Google does little to stop attackers. The report says that performance is also not a good reason, citing research showing that loading and rendering ads degrades browser performance.
Explicitly or implicitly, Google’s advertising arm seems to have an increasing influence on Chrome’s design. The company refuses to block tracking cookies until it builds a tracking and advertising system directly in Chrome.
Several extension developers are working on solutions in the Manifest V3 sandbox. It’s impossible to know the impact on the end user until these solutions are developed and Google kills the existing extension platform, but the high-profile introduction of user-hostile changes seems to be one of the few things that could hurt Chrome’s market share. Firefox still exists, along with an endless number of forks of Chromium.