Google is considering major changes to Chromium, the open-source software that powers the Google Chrome browser as well as Chrome OS and several other browsers, including Opera, Vivaldi, Brave, and soon Microsoft Edge. The proposed changes require Chrome extensions to change the way they interact with a web page's content. The idea behind the change is to stop extensions from acting as middlemen, because that's an extra step that can slow down a page's loading. The changes are described in a public document published by the Chromium development team, and discussions are taking place on the Chromium bug reporting portal.
Many ad blockers use the Chrome webRequest API to filter (as defined in each extension's block list) HTTP traffic originating from known ad sources. According to the Manifest, this API could lose its ability to be used to block content. One point states: "In Manifest V3, we will work to deprecate the blocking version of webRequest, removing blocking options from most events (they will exist as simple observers). Content blockers should use declarativeNetRequest."
The proposed API, declarativeNetRequest, would significantly limit the ways extensions can be used to filter Web traffic. It is limited to only 30,000 entries and does not allow for rules such as blocking content beyond a certain size, blocking JavaScript, and stripping headers from cookies. These are the objections raised by Raymond Hill, developer of the popular extensions uBlock Origin and uMatrix.
Hill says that the declarativeNetRequest API favors other extensions, particularly AdBlockPlus, but deprecating webRequest would completely disable uBlockOrigin and uMatrix.
Other extension developers have also voiced their objections. The Chromium team refused to acknowledge it as a bug, but a discussion was opened on the Chromium Google Group, which is still ongoing.
The full reasoning, as presented in the document, is as follows: “Currently, with the webRequest permission, an extension can delay a request for an arbitrary amount of time, since Chrome must wait for the result from the extension to continue processing the request. The basic flow is that when a request is initiated, Chrome sends information about it to the interested extensions, and the extensions respond indicating what action should be taken. This process can be relatively complex and time-consuming. This can have a significant impact on every request, even those that are not modified, redirected, or blocked by the extension (since Chrome must send the event to the extension to determine the result).”.
As The Register points out, AdBlockPlus uses much more basic filtering than other extensions, but it has also been reported to work for a fee with ad networks, including Google, and to allow some ads to be shown to users. Many users install blocking extensions not only to avoid seeing ads but also to avoid having their online activity tracked and displayed by ad networks.
