Our decision to deprecate the 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...

Read the full article at Microsoft Windows Team Blog