--- a/devtools/client/jar.mn
+++ b/devtools/client/jar.mn
@@ -1,16 +1,16 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 [features/devtools@mozilla.org] chrome.jar:
 %   content devtools %content/
     content/preferences/debugger.js (preferences/debugger.js)
-    content/preferences/devtools.js (preferences/devtools.js)
+*   content/preferences/devtools.js (preferences/devtools.js)
     content/webide/webide-prefs.js (webide/webide-prefs.js)
     content/shared/vendor/d3.js (shared/vendor/d3.js)
     content/shared/vendor/dagre-d3.js (shared/vendor/dagre-d3.js)
     content/shared/widgets/widgets.css (shared/widgets/widgets.css)
     content/netmonitor/src/assets/styles/netmonitor.css (netmonitor/src/assets/styles/netmonitor.css)
     content/shared/widgets/VariablesView.xul (shared/widgets/VariablesView.xul)
     content/netmonitor/index.html (netmonitor/index.html)
     content/webconsole/webconsole.xhtml (webconsole/webconsole.xhtml)
@@ -310,11 +310,8 @@
     skin/images/firebug/command-frames.svg (themes/images/firebug/command-frames.svg)
     skin/images/firebug/command-paintflashing.svg (themes/images/firebug/command-paintflashing.svg)
     skin/images/firebug/command-responsivemode.svg (themes/images/firebug/command-responsivemode.svg)
     skin/images/firebug/command-scratchpad.svg (themes/images/firebug/command-scratchpad.svg)
     skin/images/firebug/command-screenshot.svg (themes/images/firebug/command-screenshot.svg)
     skin/images/firebug/command-measure.svg (themes/images/firebug/command-measure.svg)
     skin/images/firebug/command-rulers.svg (themes/images/firebug/command-rulers.svg)
     skin/images/firebug/command-noautohide.svg (themes/images/firebug/command-noautohide.svg)
-
-% manifest devtools-startup.manifest
-% manifest webideComponents.manifest

--- a/devtools/client/locales/jar.mn
+++ b/devtools/client/locales/jar.mn
@@ -1,8 +1,8 @@
 #filter substitution
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 [features/devtools@mozilla.org] chrome.jar:
-% locale devtools @AB_CD@ %locale/@AB_CD@/
-  locale/@AB_CD@/ (en-US/*)
+%   locale devtools @AB_CD@ %locale/@AB_CD@/devtools/client/
+    locale/@AB_CD@/devtools/client/ (%*)

--- a/devtools/client/webide/content/jar.mn
+++ b/devtools/client/webide/content/jar.mn
@@ -1,13 +1,13 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-webide.jar:
+[features/devtools@mozilla.org] webide.jar:
 %   content webide %content/
     content/webide.xul                (webide.xul)
     content/webide.js                 (webide.js)
     content/newapp.xul                (newapp.xul)
     content/newapp.js                 (newapp.js)
     content/details.xhtml             (details.xhtml)
     content/details.js                (details.js)
     content/addons.js                 (addons.js)

--- a/devtools/client/webide/content/webide.js
+++ b/devtools/client/webide/content/webide.js
@@ -111,16 +111,22 @@ var UI = {
                                .QueryInterface(Ci.nsIDocShell)
                                .contentViewer;
     this.contentViewer.fullZoom = Services.prefs.getCharPref("devtools.webide.zoom");
 
     gDevToolsBrowser.isWebIDEInitialized.resolve();
 
     this.configureSimulator = this.configureSimulator.bind(this);
     Simulators.on("configure", this.configureSimulator);
+
+    // This allows to use mac specific selectors in webide css files, using
+    // `:root[platform="mac"]`.
+    if (navigator.platform.startsWith("Mac")) {
+      document.documentElement.setAttribute("platform", "mac");
+    }
   },
 
   destroy: function () {
     window.removeEventListener("focus", this.onfocus, true);
     AppManager.off("app-manager-update", this.appManagerUpdate);
     AppManager.destroy();
     Simulators.off("configure", this.configureSimulator);
     this.updateConnectionTelemetry();

--- a/devtools/client/webide/themes/jar.mn
+++ b/devtools/client/webide/themes/jar.mn
@@ -1,15 +1,15 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-webide.jar:
+[features/devtools@mozilla.org] webide.jar:
 % skin webide classic/1.0 %skin/
-* skin/webide.css              (webide.css)
+  skin/webide.css              (webide.css)
   skin/icons.png               (icons.png)
   skin/details.css             (details.css)
   skin/newapp.css              (newapp.css)
   skin/throbber.svg            (throbber.svg)
   skin/deck.css                (deck.css)
   skin/addons.css              (addons.css)
   skin/runtimedetails.css      (runtimedetails.css)
   skin/monitor.css             (monitor.css)

--- a/devtools/client/webide/themes/webide.css
+++ b/devtools/client/webide/themes/webide.css
@@ -133,17 +133,19 @@ window.busy-determined #action-busy-unde
 /* Main view */
 
 #deck {
   background-color: rgb(225, 225, 225);
   background-image: url('rocket.svg'), url('noise.png');
   background-repeat: no-repeat, repeat;
   background-size: 35%, auto;
   background-position: center center, top left;
-%ifndef XP_MACOSX
   border-top: 1px solid #AAA;
-%endif
+}
+
+:root[platform="mac"] #deck {
+  border-top-width: 0;
 }
 
 .devtools-horizontal-splitter {
   position: relative;
   border-bottom: 1px solid #aaa;
 }

--- a/devtools/shared/locales/jar.mn
+++ b/devtools/shared/locales/jar.mn
@@ -1,8 +1,8 @@
 #filter substitution
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-@AB_CD@.jar:
+[features/devtools@mozilla.org] chrome.jar:
 %   locale devtools-shared @AB_CD@ %locale/@AB_CD@/devtools/shared/
     locale/@AB_CD@/devtools/shared/ (%*)