---
title: "Declare data use truthfully in each store · Agent Wranglers"
url: https://agentwranglers.se/playbook/desktop-apps/browser-extensions/extension-data-disclosure
id: DSK-18
level: Recommended
updated: 2026-10-22
tokens: 811
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Declare data use truthfully in each store

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Browser extensions](https://agentwranglers.se/playbook/desktop-apps/browser-extensions.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers.md). Updated 2026-10-22.

- ID: DSK-18
- Level: Recommended
- Chapter: [Browser extensions](https://agentwranglers.se/playbook/desktop-apps/browser-extensions.md)
- Rule: Fill in the Chrome Web Store privacy practices form and Firefox's `data_collection_permissions` from one list of the data the extension sends. Link a privacy policy that says the same.
- Check: The manifest has `browser_specific_settings.gecko.data_collection_permissions`, with `"none"` when nothing leaves the browser. A test compares the data list with the hosts called during an end-to-end run. It fails on a host the list does not name.
- How: Chrome asks for a single purpose, a reason for each permission, a remote code answer and a certified list of user data collected. Since 3 November 2025, Mozilla requires new extensions to declare in the manifest whether they collect or send data. Firefox 140 and later show that list at install, and users can refuse optional items. Keep one list of data in the repository, and build the manifest key and the form text from it. This is the extension form of [fill in the store privacy forms from an SDK list](https://agentwranglers.se/playbook/mobile-apps/privacy-declarations/store-privacy-forms.md).

## Examples

**Using these examples:** they show one way to follow this rule. Keep the behaviour and the check, not the syntax. Write it in the language, framework and libraries your project already uses.

### JSON example

```json
{
  "browser_specific_settings": {
    "gecko": {
      "id": "clipper@example.com",
      "data_collection_permissions": { "required": ["none"] }
    }
  }
}
```

## Sources

- [Chrome Web Store, Fill out the privacy fields](https://developer.chrome.com/docs/webstore/cws-dashboard-privacy)
- [Firefox built-in consent for data collection](https://extensionworkshop.com/documentation/develop/firefox-builtin-data-consent/)

## Related rules

- MOB-27 [Fill in the store privacy forms from an SDK list](https://agentwranglers.se/playbook/mobile-apps/privacy-declarations/store-privacy-forms.md) in Mobile apps

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/desktop-apps/browser-extensions/extension-data-disclosure">Agent Wranglers desktop apps, extensions and CLIs playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Keep extension state in storage instead of the background worker](https://agentwranglers.se/playbook/desktop-apps/browser-extensions/worker-state-in-storage.md)
- Next: [Protect the store accounts that publish the extension](https://agentwranglers.se/playbook/desktop-apps/browser-extensions/extension-store-accounts.md)
- [Browser extensions](https://agentwranglers.se/playbook/desktop-apps/browser-extensions.md)