Google is planning to introduce a built-in ad blocker for its Chrome browser next year. While Google has already warned publishers about the change, the ad blocker is now starting to show up in pre-release versions of the Chrome for Android app. TechCrunch reports that the ad blocker can be found in the latest Chrome Canary app for Android. Testers can download the latest Chrome Canary build from Google Play to try out the ad blocker.

While Google makes the majority of its revenue through its own ad business, it’s determined to tackle what it describes as “intrusive ads.” Unacceptable ads are being determined by a group called the Coalition for Better Ads, which includes Google, Facebook, News Corp, and The Washington Post as members. The controversial addition of an ad blocker directly within Chrome will likely generate a lot of debate around Google’s control of the web and ads, and this test version will help direct that feedback to Google.

It’s not clear exactly when the ad blocker will make it into the beta or stable channels of Chrome, but Canary features often take months to reach a stable release. During our own testing at The Verge, we weren’t able to detect blocked ads, but it’s entirely possible this is a limited test right now.