Unframe chrome://extensions as it's the last (and only) uber item

chrome/browser/resources/policy.css

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
-body.uber-frame {
+body {
   -webkit-margin-start: 23px;
 }
 
-body.uber-frame > .page {
+body > .page {
   -webkit-margin-end: 0;
   -webkit-padding-end: 24px;
 }
 
 #filter-overlay {
   padding-bottom: 0;
   position: fixed;
   z-index: 4;
 }
 
-body.uber-frame header {
+body header {
   left: 23px;
   max-width: none;
 }
 
-html[dir='rtl'] body.uber-frame header {
+html[dir='rtl'] body header {
   right: 23px;
 }
 
-body.uber-frame section {
+body section {
   max-width: none;
 }
 
 #status-box-container {
   display: -webkit-flex;
 }
 
 fieldset {
   border: 1px solid rgb(217, 217, 217);
   display: inline;
@@ skipping 134 matching lines @@
   white-space: pre;
   word-wrap: break-word;
 }
 
 html:not(.focus-outline-visible)
 :enabled:focus:-webkit-any(input[type='checkbox'],
                            input[type='radio'], button) {
   /* Cancel border-color for :focus specified in widgets.css. */
   border-color: rgba(0, 0, 0, 0.25);
 }