Wikimedia Bugzilla is closed!

On zhwiki in addition to /wiki/ we have /zh-cn/ etc which act like
?variant=zh-cn. Google often index links with these variant prefix
therefore causing users to stuck on the desktop version.

Compare:

$ curl -I -H 'User-Agent: iPhone' https://zh.wikipedia.org/wiki/Foobar
HTTP/1.1 302 Found
Server: nginx/1.1.19
Date: Tue, 03 Jun 2014 16:04:19 GMT
Content-Length: 0
Connection: keep-alive
Location: https://zh.m.wikipedia.org/wiki/Foobar
Accept-Ranges: bytes
X-Varnish: 1458822202
Age: 0
Via: 1.1 varnish
X-Cache: cp4018 frontend miss (0)
Cache-Control: private, s-maxage=0, max-age=0, must-revalidate
Set-Cookie: GeoIP=::::v6; Path=/; Domain=.wikipedia.org

$ curl -I -H 'User-Agent: iPhone' https://zh.wikipedia.org/zh-cn/Foobar
HTTP/1.1 200 OK
Server: nginx/1.1.19
Date: Tue, 03 Jun 2014 16:03:40 GMT
Content-Type: text/html; charset=UTF-8
Connection: keep-alive
X-Content-Type-Options: nosniff
Cache-control: s-maxage=2678400, must-revalidate, max-age=0
Content-language: zh
X-UA-Compatible: IE=Edge
Vary: Accept-Encoding,Cookie
Last-Modified: Wed, 21 May 2014 14:34:51 GMT
X-Varnish: 437179157 425149316, 1791902241 1778144363, 2014846228
Via: 1.1 varnish, 1.1 varnish, 1.1 varnish
Age: 29564
X-Cache: cp1052 hit (1), cp4016 hit (2), cp4010 frontend miss (0)
Set-Cookie: GeoIP=::::v6; Path=/; Domain=.wikipedia.org