--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -2302,17 +2302,16 @@ GK_ATOM(_moz_windows_glass, "-moz-window
 GK_ATOM(_moz_windows_theme, "-moz-windows-theme")
 GK_ATOM(_moz_os_version, "-moz-os-version")
 GK_ATOM(_moz_touch_enabled, "-moz-touch-enabled")
 GK_ATOM(_moz_menubar_drag, "-moz-menubar-drag")
 GK_ATOM(_moz_device_pixel_ratio, "-moz-device-pixel-ratio")
 GK_ATOM(_moz_device_orientation, "-moz-device-orientation")
 GK_ATOM(_moz_is_resource_document, "-moz-is-resource-document")
 GK_ATOM(_moz_swipe_animation_enabled, "-moz-swipe-animation-enabled")
-GK_ATOM(_moz_physical_home_button, "-moz-physical-home-button")
 
 // application commands
 GK_ATOM(Back, "Back")
 GK_ATOM(Forward, "Forward")
 GK_ATOM(Reload, "Reload")
 GK_ATOM(Stop, "Stop")
 GK_ATOM(Search, "Search")
 GK_ATOM(Bookmarks, "Bookmarks")

--- a/layout/style/nsMediaFeatures.cpp
+++ b/layout/style/nsMediaFeatures.cpp
@@ -784,25 +784,16 @@ nsMediaFeatures::features[] = {
     &nsGkAtoms::_moz_swipe_animation_enabled,
     nsMediaFeature::eMinMaxNotAllowed,
     nsMediaFeature::eBoolInteger,
     nsMediaFeature::eUserAgentAndChromeOnly,
     { &nsGkAtoms::swipe_animation_enabled },
     GetSystemMetric
   },
 
-  {
-    &nsGkAtoms::_moz_physical_home_button,
-    nsMediaFeature::eMinMaxNotAllowed,
-    nsMediaFeature::eBoolInteger,
-    nsMediaFeature::eUserAgentAndChromeOnly,
-    { &nsGkAtoms::physical_home_button },
-    GetSystemMetric
-  },
-
   // Internal -moz-is-glyph media feature: applies only inside SVG glyphs.
   // Internal because it is really only useful in the user agent anyway
   //  and therefore not worth standardizing.
   {
     &nsGkAtoms::_moz_is_glyph,
     nsMediaFeature::eMinMaxNotAllowed,
     nsMediaFeature::eBoolInteger,
     nsMediaFeature::eUserAgentAndChromeOnly,