Microsoft is killing something inside Edge but it's to improve user data privacy

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Microsoft has announced that it is killing its window.external.getHostEnvironmentValue() method of gathering data related to the user device and browser. Instead, the company is moving to a more privacy-focused and standardised User-Agent Client Hints API.

It writes:

The window.external.getHostEnvironmentValue() method is an Edge-only, non-standards-based way for web developers to access information about the browser and platform. ... we’re announcing our plan to deprecate this method and we’re asking web developers to use the standardized User-Agent Client Hints API instead.

Microsoft further explains:

Our decision to deprecate the getHostEnvironmentValue() method is driven by our goal to enhance browser privacy by eliminating user fingerprinting. The UA Client Hints API provides browser and platform information in a much more privacy-preserving way as browsers can decide what to return when asked for hints. Low entropy hints are accessible with every request, while the high entropy hints that can potentially give away more fingerprinting information can be gated with user preferences or behind a permission request.

Thus, the User-Agent Client Hints API builds on the Client Hints framework to let websites access browser and platform details, and essentially, it minimizes the data footprint users leave behind when browsing while still allowing websites to get enough information to provide an optimized experience.

Microsoft has also provided a timeline for the deprecation. The company says that it will be doing so in three steps broadly and plans to fully remove it by October, which aligns with the Windows 10 support death. It writes:

To reduce interoperability issues and to gather feedback, we’re planning to deprecate the non-standard getHostEnvironmentValue() method by following these steps:

Edge version Release date Deprecation step

Edge 135 April 3, 2025 The DevTools Console warns developers when their code uses the method.
Developers can also use a feature flag to test their sites with the method disabled.

Edge 137 May 23, 2025 The method is disabled but can still be used by requesting a temporary extension for your domain.

Edge 141, depending on developer feedback October 2025 The method is fully removed from Edge.

Edge version	Release date	Deprecation step
Edge 135	April 3, 2025	The DevTools Console warns developers when their code uses the method. Developers can also use a feature flag to test their sites with the method disabled.
Edge 137	May 23, 2025	The method is disabled but can still be used by requesting a temporary extension for your domain.
Edge 141, depending on developer feedback	October 2025	The method is fully removed from Edge.

Microsoft has also added that an extension request is allowed for websites that rely on it. You can find more details about it here on the official blog post.