Site Locale Control

Version 0.1.0

On sites you choose, this extension presents the time zone, language, Intl locale, user agent, font measurements, and WebRTC candidates as the region you select. It does not change your IP address, does not upload data, and has no analytics. It is not listed on the Chrome Web Store yet, so load the unpacked folder in developer mode.

Download (121 KB)

Install

1. Download the zip and unzip it. The folder should contain manifest.json directly.
2. Open chrome://extensions.
3. Turn on Developer mode in the top-right corner.
4. Click Load unpacked and select the unzipped folder.
5. Click the toolbar icon, allow the site in the popup, and choose Apply recommended.
6. Return to this site’s check page and run the check.

Open the check page

What it changes

• Time zone and UTC offset reported by Date and Intl.DateTimeFormat.
• navigator.language / navigator.languages and the default Intl locale.
• Optional: a desktop Chrome user agent string for the selected region.
• Optional: font measurements, so locale-specific system fonts are not exposed through text metrics.
• Optional: WebRTC ICE candidates seen by the page, so local addresses are not listed.
• It does not change your operating system clock, your IP address, or anything outside the sites you allow.

Permissions and privacy

• Required permissions are only storage, scripting and declarativeNetRequestWithHostAccess. The release build requests no host permissions at install time.
• Site access is requested per site from the popup, only for the sites you add. The browser-wide WebRTC policy uses the optional privacy permission and is asked for separately.
• Settings stay in chrome.storage on your device. The extension sends no network requests of its own, has no analytics, and uploads nothing.
• The source code is open on GitHub under the extension/ folder of the project repository.

Responsible use

Site Locale Control is a diagnostic and privacy tool for checking what a web page can read about your browser locale. It does not hide your network location, and it is not a way around any service’s rules. Follow the Terms of Service of every site you use it on.

Update

After downloading a new version, replace the unpacked folder, then open chrome://extensions and click Reload.

FAQ

Why is it not on the Chrome Web Store?

It has not been submitted yet. Until then, install the unpacked folder in developer mode. Chrome may show a developer mode reminder at startup; that is expected.

My changes did not apply. What should I check?

Make sure the switch in the popup is on and the site is allowed, then reload the tab. The extension does not reload pages automatically.

Which browsers are supported?

Desktop Chrome with Manifest V3. Other Chromium browsers that load unpacked extensions usually work but are not tested.

How do I remove it?

Open chrome://extensions and click Remove on Site Locale Control. Its stored settings are deleted with it.