Privacy vs. Profit: The Impact of Google's Manifest Version 3 (MV3) Update on Ad Blocker Effectiveness

Authors: Karlo Lukic and Lazaros Papadopoulos

Affiliation: Goethe University Frankfurt

Venue: Proceedings on Privacy Enhancing Technologies (PoPETs), Volume 2026, Issue 1

Artifact: ARTIFACT-APPENDIX.md | Targeting: Available, Functional, Reproduced badges

Abstract

Google's recent update to the manifest file for Chrome browser extensions, transitioning from manifest version 2 (MV2) to manifest version 3 (MV3), has raised concerns among users and ad blocker providers, who worry that the new restrictions, notably the shift from the powerful WebRequest API to the more restrictive DeclarativeNetRequest API, might reduce ad blocker effectiveness. Because ad blockers play a vital role for millions of users seeking a more private and ad-free browsing experience, this study empirically investigates how the MV3 update affects their ability to block ads and trackers.

Through a browser-based experiment conducted across multiple samples of ad-supported websites, we compare the MV3 to MV2 instances of four widely used ad blockers. Our results reveal no statistically significant reduction in ad-blocking or anti-tracking effectiveness for MV3 ad blockers compared to their MV2 counterparts, and in some cases, MV3 instances even exhibit slight improvements in blocking trackers. These findings are reassuring for users, indicating that the MV3 instances of popular ad blockers continue to provide effective protection against intrusive ads and privacy-infringing trackers. While some uncertainties remain, ad blocker providers appear to have successfully navigated the MV3 update, finding solutions that maintain the core functionality of their extensions.

Repository Structure

Directory	Contents
01_data/	Datasets (.rds, .xlsx) and browser extensions
02_scripts/01_py/	Python crawler scripts (data collection)
02_scripts/02_R/	R analysis scripts (reproducible analysis)
03_results/	Generated figures (.pdf) and tables (.tex)
renv/	R environment management
renv.lock	R dependency versions

Research Pipeline

flowchart LR
    subgraph collect["Data Collection"]
        A[(Websites)] --> B[Browser Experiment]
        B --> C[(HTTP Logs)]
    end

    subgraph process["Processing"]
        C --> D[WhoTracks.me]
        D --> E[(Dataset)]
    end

    subgraph analyze["R Analysis"]
        E --> F[Statistics]
        F --> G[Figures/Tables]
    end

    style collect fill:#ffe6e6
    style process fill:#e6f3ff
    style analyze fill:#e6ffe6

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Reproducibility Note:

• Part 1 (Data Collection): Scripts provided for methodology transparency. May require adjustments due to Chrome/extension updates since data collection.
• Part 3 (Analysis): Fully reproducible from provided datasets. Generates all paper figures and tables.

Quick Start (R Analysis)

Prerequisites

• R 4.4+ (download)
• RStudio (recommended) or terminal
• gfortran (required for compiling some R packages)

Steps

# 1. Clone the repository
git clone https://github.com/karlolukic/impact-of-google-mv3-on-ad-blocker-effectivenesss.git
cd impact-of-google-mv3-on-ad-blocker-effectivenesss

# 2. Open R and restore dependencies
R

# In R console:
renv::restore()  # Install all required packages

# 3. Run the analysis
source("02_scripts/02_R/reproducible_analysis.R")

Output: Figures and tables saved to 03_results/

Alternative Formats

The analysis is available in three formats:

Format	File	Run Command
R Script	reproducible_analysis.R	source(...)
Quarto	reproducible_analysis.qmd	quarto render ...
Jupyter	reproducible_analysis.ipynb	Jupyter with R kernel

Docker Reproduction (Recommended)

For fully reproducible results, use Docker to build and run the analysis in an isolated environment:

# Build the Docker image
docker build -t mv3-artifact .

# Run analysis and generate outputs
docker run --rm -v $(pwd)/03_results:/artifact/03_results mv3-artifact

# Verify outputs match reference checksums
docker run --rm mv3-artifact Rscript verify_outputs.R

Expected runtime: ~25 minutes (Docker build ~20 min, analysis ~5 min)

The Docker image includes:

• R 4.4.2 with all required packages (via renv)
• All system dependencies pre-installed
• Automatic verification of output integrity

Ad Blockers Tested

Ad Blocker	MV2 Instance	MV3 Instance
Adblock Plus	Adblock Plus - free ad blocker (v3.25.1)	Adblock Plus - free ad blocker (v4.5.1)
AdGuard	AdGuard AdBlocker (v4.3.53)	AdGuard AdBlocker MV3 Beta (v5.0.33)
Stands	Stands AdBlocker (v2.1.24)	Fair AdBlocker MV3 Beta (v2.1.10)
uBlock	uBlock Origin (v1.59.0)	uBlock Origin Lite (v2024.8.12.902)

Key Findings

1. No significant effectiveness reduction: MV3 ad blockers perform comparably to MV2 versions
2. Improved tracker blocking: Some MV3 versions showed enhanced anti-tracking capabilities
3. Successful adaptation: Ad blocker developers effectively adapted to new API constraints

Citation

If you use this artifact, please cite our paper:

@article{lukic2025privacy,
  title={Privacy vs. Profit: The Impact of Google's Manifest Version 3 (MV3) Update on Ad Blocker Effectiveness},
  author={Lukic, Karlo and Papadopoulos, Lazaros},
  journal={Proceedings on Privacy Enhancing Technologies},
  year={2026}
}

Acknowledgments

This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 833714). Lazaros Papadopoulos acknowledges financial support from the German Academic Exchange Service (DAAD) and the German Research Foundation (DFG) under the TRR266 program (Project-ID 403041268).

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contact

• Karlo Lukic - GitHub
• Lazaros Papadopoulos

For questions about the artifact, please open an issue.