Last updated: May 2026
Eidolon operates entirely on your device. It collects no personal information, sends no data to any server, and requires no account.
1. What Eidolon Does
Eidolon is a browser privacy extension that detects and blocks third-party tracking requests, identifies browser fingerprinting attempts, and calculates a per-site privacy risk score. All of this happens locally inside your browser. No information about your browsing leaves your device.
2. Data Collected and How It Is Used
Eidolon records the following information in your browser's local storage solely to power the popup display and dashboard:
| Data | Where It Lives | Purpose | Sent Anywhere? |
|---|---|---|---|
| Blocked request URLs and domains | Local Chrome storage (session only) | Display threat counts and category breakdown in popup | No |
| Fingerprint probe detections (e.g. AudioContext, WebGL) | Local Chrome storage (session only) | Display detected fingerprinting techniques in popup | No |
| Per-tab privacy score | Computed in memory | Score ring displayed in popup and dashboard | No |
| Extension settings (on/off toggles) | Local Chrome storage (persisted) | Remember your preferences between sessions | No |
This data is never transmitted over the network, never written to a remote database, and is not accessible to any website or third party. Blocked request records are cleared when you close a tab or restart the browser.
3. Permissions Used
The extension requests the following Chrome permissions, each for a specific functional reason:
| Permission | Why It Is Needed |
|---|---|
declarativeNetRequest |
Block tracker and fingerprinting script requests before they load |
declarativeNetRequestFeedback |
Observe which requests were blocked so they can be shown in the dashboard |
scripting |
Inject fingerprint detector scripts into page contexts to detect probing |
storage |
Save blocked-request records and settings locally on your device |
tabs |
Associate privacy scores and blocked counts with the correct browser tab |
activeTab |
Read the URL of the currently active tab to display its privacy score |
webRequest |
Observe outgoing requests to classify them against the tracker domain list |
host_permissions: <all_urls> |
Required to inject fingerprint detectors and observe requests on all websites |
4. Data Sharing
Eidolon does not share any data with third parties. There is no analytics, no telemetry, no crash reporting service, and no advertising SDK embedded in this extension. The tracker domain list used for blocking is compiled into the extension at build time and does not make network requests to update itself.
5. Children's Privacy
Eidolon does not knowingly collect any information from users of any age. Because no personal data is collected at all, the extension does not implicate children's privacy regulations such as COPPA.
6. Changes to This Policy
If this policy changes materially, the updated version will be published at this URL and the "Last updated" date above will be revised. Continued use of the extension after a policy change constitutes acceptance of the updated terms.
7. Contact
Questions or concerns about this privacy policy can be directed to the project's GitHub repository: github.com/MatthewDawkins/security-portfolio