Closed-source browser extension Pie Adblock was this week accused of copying code and text from rival uBlock Origin in violation of the latter’s software license – the GNU GPL version 3.
Since that claim was made and The Register inquired about the matter, Pie Adblock’s maker published materials in the past few hours that are at the heart of the extension and clearly come from uBlock Origin as well as Adguard, another competitor.
That publication states the files, used by Pie AdBlock to block adverts on the web, contain “modified versions of text rules from [uBlock Origin’s] uAssets and scriplets from AdGuard Scriptlets, which is also licensed under the GPL v3 license … Repository open source licensed under GNU GPL v3 license.”
Thus, Pie Adblock was accused of lifting code and text from the GPL’d uBlock Origin, at least, without meeting the GPL’s requirements – such as stating who owns the copyright on those components and how they can be obtained – and now its developer has made at least some material publicly available and acknowledged the authors as uBlock Origin and Adguard.
The Pie Adblock team also argued it met and meets all the necessary requirements, and is sharing the data due to “the importance of contributing back.”
Honey trap
Pie Adblock was released last year by a startup called The People’s Internet Experiment, aka pie.org, which was founded by Ryan Hudson, co-founder of Honey – the browser extension acquired by PayPal in 2020 for $4 billion, which is now facing at least one lawsuit [PDF] alleging affiliate fraud. Honey denies any wrongdoing.
Hudson launched pie.org last year, offering an ad-blocking browser extension – available for desktop Google Chrome – that pays you if you choose to see certain adverts. As of the end of December 2024, Pie Adblock had racked up more than one million users.
More specifically, the extension provides a Rewards for Ads program that gives points to users who willingly view selected adverts while others are blocked. These reward points, the outfit says, “can be redeemed for cash back.”
Though Pie Adblock also makes money through affiliate commissions, the extension does not engage in the affiliate code replacement Honey is alleged to have quietly pulled off, Hudson told us.
Regarding the legal action against it, a spokesperson for Honey told us on Friday: “We dispute the allegations in the lawsuits, and will defend against them vigorously. Honey is free to use and provides millions of shoppers with additional savings on their purchases whenever possible. Honey helps merchants reduce cart abandonment and comparison shopping while increasing sales conversion.”
License to grill
After the spotlight was turned on Honey over the Christmas break, attention moved to Pie Adblock, leading to this week’s allegations of code misuse.
Social media sleuths posting to Reddit claimed Pie Adblock had incorporated code and files from uBlock Origin including the latter’s Quick Fixes filter list without the necessary acknowledgements and other requirements.
And indeed when The Register checked the extension’s files using the Chrome Extension Source Viewer, the Pie Adblock file adblock-rulesets/included-filters/ubo-ads.txt included a link to the uBlock Origin uAssets repo’s GPL v3 license.
Other files in the Pie Adblock extension also appeared to incorporate uBlock Origin source code.
Source code made available under the GNU GPL v3, such as uBlock Origin’s code, is intended to be shared and used in other projects, subject to the license requirements. One of those requirements, besides including the original copyright notice, is that the license under which that software is offered should be clear.
And until just a few hours ago, the Pie Adblock extension did not clearly state the licensing terms of some parts of its product; now it does, albeit on a GitHub repo that we can’t see linked to from any Pie Adblock webpages.
The company’s terms of service also impose various limitations that appear to be incompatible with GPL freedoms. For example, users may not “duplicate, decompile, reverse engineer, disassemble or decode the services (including any underlying idea or algorithm), or attempt to do any of the same.” The Pie Adblock Extension is explicitly defined as one of the biz’s services. Another passage disallows copying or modifying services, rights the GPL v3 supports.
The GPL is enforceable, as far as the courts in the US are concerned, but the time and expense of doing so means such cases are rare. One such claim against Vizio, filed in 2021 by the Software Freedom Conservancy, is expected to be tried in September 2025.
Hudson told The Register his company is aware of the concerns, and said he takes community feedback seriously. But he contends Pie Adblock meets the GPL v3 requirements, telling us:
Interestingly enough, it was claimed Pie AdBlock used uBlock Origin code and filter lists, though so far Pie AdBlock acknowledges using just the filter texts.
Asked about Pie Adblock, Raymond Hill, creator of uBlock Origin, told The Register, “I noticed this weeks ago but shrugged it off. Many other content blocker extensions in the Chrome store are doing the same or worse, using the whole code base. It has always been like this.”
Hill pointed to a series of posts he made in June 2024 about “sleazy rip-offs in the Chrome Web Store” that simply rewrap “uBlock, uBlock Lite, or other content blockers with their own user interface,” and some monetization scheme, often removing the copyright and licensing information. ®
