On a related note W3C+Mozilla are trying to document use-cases for UA sniffing: https://etherpad.mozilla.org/uadetection-usecases
[0] http://www.nczonline.net/blog/2013/07/02/internet-explorer-1...
The user-agent header is an artifact of history, and should be abolished. I can see no use case for it aside from standards-avoidance.
That's true, but one's platonic idea of the browser does take a backseat to reality.
On a related note W3C+Mozilla are trying to document use-cases for UA sniffing: https://etherpad.mozilla.org/uadetection-usecases