After you install the update and enable the web filtering feature in Microsoft Family Safety, Internet Explorer adds a “prefer: safe” HTTP header to every HTTP request to indicate that the user prefers a family-friendly browsing experience. Web sites that receive this header should filter out adult material that is unsuitable for children when the web sites respond to the HTTP requests. The header is not widely supported by web sites today. However, we hope to see sites voluntarily use the header over time. Microsoft Bing supports the header as a way to turn on the Safe Search feature for Bing, and this removes links to adult material from search results. The safe preference feature is supported by Internet Explorer 11 and Internet Explorer 10.
This specification defines a “safe” preference for HTTP, expressing a user preference to avoid “objectionable” content.