Manual:$wgHandheldForIPhone

Frontend: $wgHandheldForIPhone
Apply "screen" and "handheld" media also apply to the iPhone/iPod Touch Mobile Safari.
Introduced in version:1.14.0 (r38116)
Removed in version:1.22.0 (Gerrit change 63343; git #I7c24128)
Allowed values:(boolean)
Default value:false

Details edit

Apply "screen" and "handheld" media specifiers for style sheets are transformed such that they apply to the iPhone/iPod Touch Mobile Safari, which doesn't recognize "handheld" but does support media queries on its screen size.

Consider only using this if you have a *really good* handheld stylesheet, as iPhone users won't have any way to disable it and use the "grown-up" styles instead.