--- a/devtools/client/inspector/inspector.js
+++ b/devtools/client/inspector/inspector.js
@@ -876,21 +876,16 @@ Inspector.prototype = {
           this.browserRequire("devtools/client/inspector/fonts/fonts");
         panel = new FontInspector(this, this.panelWin);
         break;
       case "layoutview":
         const LayoutView =
           this.browserRequire("devtools/client/inspector/layout/layout");
         panel = new LayoutView(this, this.panelWin);
         break;
-      case "newruleview":
-        const RulesView =
-          this.browserRequire("devtools/client/inspector/rules/new-rules");
-        panel = new RulesView(this, this.panelWin);
-        break;
       case "ruleview":
         const {RuleViewTool} = require("devtools/client/inspector/rules/rules");
         panel = new RuleViewTool(this, this.panelWin);
         break;
       default:
         // This is a custom panel or a non lazy-loaded one.
         return null;
     }
@@ -961,23 +956,16 @@ Inspector.prototype = {
       // Insert Changes as third tab, right after Computed.
       // TODO: move this inline to `sidebarPanels` above when addressing Bug 1491887.
       sidebarPanels.splice(2, 0, {
         id: "changesview",
         title: INSPECTOR_L10N.getStr("inspector.sidebar.changesViewTitle"),
       });
     }
 
-    if (Services.prefs.getBoolPref("devtools.inspector.new-rulesview.enabled")) {
-      sidebarPanels.push({
-        id: "newruleview",
-        title: INSPECTOR_L10N.getStr("inspector.sidebar.ruleViewTitle"),
-      });
-    }
-
     for (const { id, title } of sidebarPanels) {
       // The Computed panel is not a React-based panel. We pick its element container from
       // the DOM and wrap it in a React component (InspectorTabPanel) so it behaves like
       // other panels when using the Inspector's tool sidebar.
       if (id === "computedview") {
         this.sidebar.queueExistingTab(id, title, defaultTab === id);
       } else {
         // When `panel` is a function, it is called when the tab should render. It is

--- a/devtools/client/inspector/reducers.js
+++ b/devtools/client/inspector/reducers.js
@@ -12,9 +12,8 @@ exports.boxModel = require("devtools/cli
 exports.changes = require("devtools/client/inspector/changes/reducers/changes");
 exports.extensionsSidebar = require("devtools/client/inspector/extensions/reducers/sidebar");
 exports.flexbox = require("devtools/client/inspector/flexbox/reducers/flexbox");
 exports.fontOptions = require("devtools/client/inspector/fonts/reducers/font-options");
 exports.fontData = require("devtools/client/inspector/fonts/reducers/fonts");
 exports.fontEditor = require("devtools/client/inspector/fonts/reducers/font-editor");
 exports.grids = require("devtools/client/inspector/grids/reducers/grids");
 exports.highlighterSettings = require("devtools/client/inspector/grids/reducers/highlighter-settings");
-exports.rules = require("devtools/client/inspector/rules/reducers/rules");

deleted file mode 100644
--- a/devtools/client/inspector/rules/actions/index.js
+++ /dev/null
@@ -1,14 +0,0 @@
-/* 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/. */
-
-"use strict";
-
-const { createEnum } = require("devtools/client/shared/enum");
-
-createEnum([
-
-  // Update the entire rules state with the new list of rules.
-  "UPDATE_RULES",
-
-], module.exports);

deleted file mode 100644
--- a/devtools/client/inspector/rules/actions/moz.build
+++ /dev/null
@@ -1,7 +0,0 @@
-# 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/.
-
-DevToolsModules(
-    'index.js',
-)

deleted file mode 100644
--- a/devtools/client/inspector/rules/components/RulesApp.js
+++ /dev/null
@@ -1,35 +0,0 @@
-/* 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/. */
-
-"use strict";
-
-const { PureComponent } = require("devtools/client/shared/vendor/react");
-const dom = require("devtools/client/shared/vendor/react-dom-factories");
-const { connect } = require("devtools/client/shared/vendor/react-redux");
-
-const { getStr } = require("../utils/l10n");
-
-class RulesApp extends PureComponent {
-  static get propTypes() {
-    return {};
-  }
-
-  render() {
-    return dom.div(
-      {
-        id: "sidebar-panel-ruleview",
-        className: "theme-sidebar inspector-tabpanel",
-      },
-      dom.div(
-        {
-          id: "ruleview-no-results",
-          className: "devtools-sidepanel-no-result",
-        },
-        getStr("rule.empty")
-      )
-    );
-  }
-}
-
-module.exports = connect(state => state)(RulesApp);

deleted file mode 100644
--- a/devtools/client/inspector/rules/components/moz.build
+++ /dev/null
@@ -1,7 +0,0 @@
-# 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/.
-
-DevToolsModules(
-    'RulesApp.js',
-)

--- a/devtools/client/inspector/rules/moz.build
+++ b/devtools/client/inspector/rules/moz.build
@@ -1,24 +1,19 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # 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/.
 
 DIRS += [
-    'actions',
-    'components',
     'models',
-    'reducers',
-    'utils',
     'views',
 ]
 
 DevToolsModules(
-    'new-rules.js',
     'rules.js',
 )
 
 BROWSER_CHROME_MANIFESTS += ['test/browser.ini']
 
 with Files('**'):
     BUG_COMPONENT = ('DevTools', 'CSS Rules Inspector')

deleted file mode 100644
--- a/devtools/client/inspector/rules/new-rules.js
+++ /dev/null
@@ -1,50 +0,0 @@
-/* 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/. */
-
-"use strict";
-
-const { createFactory, createElement } = require("devtools/client/shared/vendor/react");
-const { Provider } = require("devtools/client/shared/vendor/react-redux");
-
-const RulesApp = createFactory(require("./components/RulesApp"));
-
-const { LocalizationHelper } = require("devtools/shared/l10n");
-const INSPECTOR_L10N =
-  new LocalizationHelper("devtools/client/locales/inspector.properties");
-
-class RulesView {
-  constructor(inspector, window) {
-    this.document = window.document;
-    this.inspector = inspector;
-    this.store = inspector.store;
-
-    this.init();
-  }
-
-  init() {
-    if (!this.inspector) {
-      return;
-    }
-
-    const rulesApp = RulesApp({});
-
-    const provider = createElement(Provider, {
-      id: "ruleview",
-      key: "ruleview",
-      store: this.store,
-      title: INSPECTOR_L10N.getStr("inspector.sidebar.ruleViewTitle")
-    }, rulesApp);
-
-    // Expose the provider to let inspector.js use it in setupSidebar.
-    this.provider = provider;
-  }
-
-  destroy() {
-    this.document = null;
-    this.inspector = null;
-    this.store = null;
-  }
-}
-
-module.exports = RulesView;

deleted file mode 100644
--- a/devtools/client/inspector/rules/reducers/moz.build
+++ /dev/null
@@ -1,7 +0,0 @@
-# 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/.
-
-DevToolsModules(
-    'rules.js',
-)

deleted file mode 100644
--- a/devtools/client/inspector/rules/reducers/rules.js
+++ /dev/null
@@ -1,19 +0,0 @@
-/* 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/. */
-
-"use strict";
-
-const INITIAL_RULES = {};
-
-const reducers = {
-
-};
-
-module.exports = function(rules = INITIAL_RULES, action) {
-  const reducer = reducers[action.type];
-  if (!reducer) {
-    return rules;
-  }
-  return reducer(rules, action);
-};

deleted file mode 100644
--- a/devtools/client/inspector/rules/utils/l10n.js
+++ /dev/null
@@ -1,13 +0,0 @@
-/* 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/. */
-
-"use strict";
-
-const { LocalizationHelper } = require("devtools/shared/l10n");
-const L10N = new LocalizationHelper("devtools/shared/locales/styleinspector.properties");
-
-module.exports = {
-  getStr: (...args) => L10N.getStr(...args),
-  getFormatStr: (...args) => L10N.getFormatStr(...args),
-};

deleted file mode 100644
--- a/devtools/client/inspector/rules/utils/moz.build
+++ /dev/null
@@ -1,9 +0,0 @@
-# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# 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/.
-
-DevToolsModules(
-    'l10n.js',
-)

--- a/devtools/client/preferences/devtools-client.js
+++ b/devtools/client/preferences/devtools-client.js
@@ -51,18 +51,16 @@ pref("devtools.inspector.showAllAnonymou
 // Show user agent shadow roots
 pref("devtools.inspector.showUserAgentShadowRoots", false);
 // Enable the CSS shapes highlighter
 pref("devtools.inspector.shapesHighlighter.enabled", true);
 // Enable the font highlight-on-hover feature
 pref("devtools.inspector.fonthighlighter.enabled", true);
 // Enable tracking of style changes and the Changes panel in the Inspector
 pref("devtools.inspector.changes.enabled", true);
-// Enable the new Rules View
-pref("devtools.inspector.new-rulesview.enabled", false);
 
 // Flexbox preferences
 pref("devtools.inspector.flexboxHighlighter.enabled", true);
 pref("devtools.flexboxinspector.enabled", true);
 
 // Grid highlighter preferences
 pref("devtools.gridinspector.gridOutlineMaxColumns", 50);
 pref("devtools.gridinspector.gridOutlineMaxRows", 50);