diff --git a/core/modules/system/templates/install-page.html.twig b/core/modules/system/templates/install-page.html.twig
index 1d0e479..4f3a995 100644
--- a/core/modules/system/templates/install-page.html.twig
+++ b/core/modules/system/templates/install-page.html.twig
@@ -13,7 +13,7 @@
 #}
   <div class="layout-container">
 
-    <header role="banner">
+    <header>
       {% if site_name or site_slogan %}
         <div class="name-and-slogan">
           {% if site_name %}
@@ -26,7 +26,7 @@
       {% endif %}
     </header>
 
-    <main role="main">
+    <main>
       {% if title %}
         <h1>{{ title }}</h1>
       {% endif %}
@@ -35,13 +35,13 @@
     </main>
 
     {% if page.sidebar_first %}
-      <aside class="layout-sidebar-first" role="complementary">
+      <aside class="layout-sidebar-first">
         {{ page.sidebar_first }}
       </aside>{# /.layout-sidebar-first #}
     {% endif %}
 
     {% if page.sidebar_second %}
-      <aside class="layout-sidebar-second" role="complementary">
+      <aside class="layout-sidebar-second">
         {{ page.sidebar_second }}
       </aside>{# /.layout-sidebar-second #}
     {% endif %}
diff --git a/core/modules/system/templates/maintenance-page.html.twig b/core/modules/system/templates/maintenance-page.html.twig
index 748ed5a..8469656 100644
--- a/core/modules/system/templates/maintenance-page.html.twig
+++ b/core/modules/system/templates/maintenance-page.html.twig
@@ -11,7 +11,7 @@
  * @ingroup themeable
  */
 #}
-<header role="banner">
+<header>
   {% if logo %}
     <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home">
       <img src="{{ logo }}" alt="{{ 'Home'|t }}"/>
@@ -31,7 +31,7 @@
   {% endif %}
 </header>
 
-<main role="main">
+<main>
   {% if title %}
     <h1>{{ title }}</h1>
   {% endif %}
@@ -42,13 +42,13 @@
 </main>
 
 {% if page.sidebar_first %}
-  <aside role="complementary">
+  <aside>
     {{ page.sidebar_first }}
   </aside>
 {% endif %}
 
 {% if page.sidebar_second %}
-  <aside role="complementary">
+  <aside>
     {{ page.sidebar_second }}
   </aside>
 {% endif %}
diff --git a/core/modules/system/templates/page.html.twig b/core/modules/system/templates/page.html.twig
index 032b724..2469407 100644
--- a/core/modules/system/templates/page.html.twig
+++ b/core/modules/system/templates/page.html.twig
@@ -47,7 +47,7 @@
 #}
 <div class="layout-container">
 
-  <header role="banner">
+  <header>
     {{ page.header }}
   </header>
 
@@ -60,7 +60,7 @@
 
   {{ page.help }}
 
-  <main role="main">
+  <main>
     <a id="main-content" tabindex="-1"></a>{# link is in html.html.twig #}
 
     <div class="layout-content">
@@ -68,13 +68,13 @@
     </div>{# /.layout-content #}
 
     {% if page.sidebar_first %}
-      <aside class="layout-sidebar-first" role="complementary">
+      <aside class="layout-sidebar-first">
         {{ page.sidebar_first }}
       </aside>
     {% endif %}
 
     {% if page.sidebar_second %}
-      <aside class="layout-sidebar-second" role="complementary">
+      <aside class="layout-sidebar-second">
         {{ page.sidebar_second }}
       </aside>
     {% endif %}
diff --git a/core/themes/bartik/templates/maintenance-page.html.twig b/core/themes/bartik/templates/maintenance-page.html.twig
index 3cd787b..9e9b309 100644
--- a/core/themes/bartik/templates/maintenance-page.html.twig
+++ b/core/themes/bartik/templates/maintenance-page.html.twig
@@ -10,7 +10,7 @@
  #}
 <div id="page-wrapper">
   <div id="page">
-    <header id="header" role="banner">
+    <header id="header">
       <div class="section clearfix">
         {% if site_name or site_slogan %}
           <div id="name-and-slogan"{{ hide_site_name and hide_site_slogan ? ' class="visually-hidden"' }}>
@@ -32,7 +32,7 @@
     </header>
     <div id="main-wrapper">
       <div id="main" class="clearfix">
-        <main id="content" class="column" role="main">
+        <main id="content" class="column">
           <section class="section">
             <a id="main-content"></a>
             {% if title %}
diff --git a/core/themes/bartik/templates/page.html.twig b/core/themes/bartik/templates/page.html.twig
index 6fefe94..b783de3 100644
--- a/core/themes/bartik/templates/page.html.twig
+++ b/core/themes/bartik/templates/page.html.twig
@@ -52,7 +52,7 @@
 #}
 <div id="page-wrapper">
   <div id="page">
-    <header id="header" class="header" role="banner" aria-label="{{ 'Site header'|t}}">
+    <header id="header" class="header" aria-label="{{ 'Site header'|t}}">
       <div class="section layout-container clearfix">
         {{ page.secondary_menu }}
         {{ page.header }}
@@ -61,14 +61,14 @@
     </header>
     {% if page.highlighted %}
       <div class="highlighted">
-        <aside class="layout-container section clearfix" role="complementary">
+        <aside class="layout-container section clearfix">
           {{ page.highlighted }}
         </aside>
       </div>
     {% endif %}
     {% if page.featured_top %}
       <div class="featured-top">
-        <aside class="featured-top__inner section layout-container clearfix" role="complementary">
+        <aside class="featured-top__inner section layout-container clearfix">
           {{ page.featured_top }}
         </aside>
       </div>
@@ -76,7 +76,7 @@
     <div id="main-wrapper" class="layout-main-wrapper layout-container clearfix">
       <div id="main" class="layout-main clearfix">
         {{ page.breadcrumb }}
-        <main id="content" class="column main-content" role="main">
+        <main id="content" class="column main-content">
           <section class="section">
             <a id="main-content" tabindex="-1"></a>
             {{ page.content }}
@@ -84,14 +84,14 @@
         </main>
         {% if page.sidebar_first %}
           <div id="sidebar-first" class="column sidebar">
-            <aside class="section" role="complementary">
+            <aside class="section">
               {{ page.sidebar_first }}
             </aside>
           </div>
         {% endif %}
         {% if page.sidebar_second %}
           <div id="sidebar-second" class="column sidebar">
-            <aside class="section" role="complementary">
+            <aside class="section">
               {{ page.sidebar_second }}
             </aside>
           </div>
@@ -100,7 +100,7 @@
     </div>
     {% if page.featured_bottom_first or page.featured_bottom_second or page.featured_bottom_third %}
       <div class="featured-bottom">
-        <aside class="layout-container clearfix" role="complementary">
+        <aside class="layout-container clearfix">
           {{ page.featured_bottom_first }}
           {{ page.featured_bottom_second }}
           {{ page.featured_bottom_third }}
diff --git a/core/themes/classy/templates/layout/maintenance-page.html.twig b/core/themes/classy/templates/layout/maintenance-page.html.twig
index 7463b02..2b8e2ab 100644
--- a/core/themes/classy/templates/layout/maintenance-page.html.twig
+++ b/core/themes/classy/templates/layout/maintenance-page.html.twig
@@ -11,7 +11,7 @@
 #}
 <div class="layout-container">
 
-  <header role="banner">
+  <header>
     {% if logo %}
       <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home">
         <img src="{{ logo }}" alt="{{ 'Home'|t }}"/>
@@ -34,7 +34,7 @@
 
   </header>
 
-  <main role="main">
+  <main>
     {% if title %}
       <h1>{{ title }}</h1>
     {% endif %}
@@ -45,13 +45,13 @@
   </main>
 
   {% if page.sidebar_first %}
-    <aside class="layout-sidebar-first" role="complementary">
+    <aside class="layout-sidebar-first">
       {{ page.sidebar_first }}
     </aside>{# /.layout-sidebar-first #}
   {% endif %}
 
   {% if page.sidebar_second %}
-    <aside class="layout-sidebar-second" role="complementary">
+    <aside class="layout-sidebar-second">
       {{ page.sidebar_second }}
     </aside>{# /.layout-sidebar-second #}
   {% endif %}
diff --git a/core/themes/classy/templates/layout/page.html.twig b/core/themes/classy/templates/layout/page.html.twig
index aee34f6..c32d8a2 100644
--- a/core/themes/classy/templates/layout/page.html.twig
+++ b/core/themes/classy/templates/layout/page.html.twig
@@ -45,7 +45,7 @@
 #}
 <div class="layout-container">
 
-  <header role="banner">
+  <header>
     {{ page.header }}
   </header>
 
@@ -58,7 +58,7 @@
 
   {{ page.help }}
 
-  <main role="main">
+  <main>
     <a id="main-content" tabindex="-1"></a>{# link is in html.html.twig #}
 
     <div class="layout-content">
@@ -66,13 +66,13 @@
     </div>{# /.layout-content #}
 
     {% if page.sidebar_first %}
-      <aside class="layout-sidebar-first" role="complementary">
+      <aside class="layout-sidebar-first">
         {{ page.sidebar_first }}
       </aside>
     {% endif %}
 
     {% if page.sidebar_second %}
-      <aside class="layout-sidebar-second" role="complementary">
+      <aside class="layout-sidebar-second">
         {{ page.sidebar_second }}
       </aside>
     {% endif %}
diff --git a/core/themes/seven/css/theme/maintenance-page.css b/core/themes/seven/css/theme/maintenance-page.css
index 3725ac6..ad02eca 100644
--- a/core/themes/seven/css/theme/maintenance-page.css
+++ b/core/themes/seven/css/theme/maintenance-page.css
@@ -25,7 +25,7 @@
  * Task list & step indicator
  */
 @media all and (max-width: 48em) { /* 768px */
-  header[role="banner"] {
+  header {
     position: relative;
   }
   .step-indicator {
diff --git a/core/themes/seven/js/mobile.install.js b/core/themes/seven/js/mobile.install.js
index e7a0b5c..09d6ab7 100644
--- a/core/themes/seven/js/mobile.install.js
+++ b/core/themes/seven/js/mobile.install.js
@@ -18,7 +18,7 @@
   function installStepsSetup() {
     var steps = document.querySelectorAll('.task-list li');
     if (steps.length) {
-      var header = document.querySelector('header[role="banner"]');
+      var header = document.querySelector('header');
       var stepIndicator = document.createElement('div');
       stepIndicator.className = 'step-indicator';
       stepIndicator.innerHTML = findActiveStep(steps) + '/' + steps.length;
diff --git a/core/themes/seven/templates/install-page.html.twig b/core/themes/seven/templates/install-page.html.twig
index 2ada24d..86300f6 100644
--- a/core/themes/seven/templates/install-page.html.twig
+++ b/core/themes/seven/templates/install-page.html.twig
@@ -11,7 +11,7 @@
 #}
 <div class="layout-container">
 
-  <header role="banner">
+  <header>
     {% if site_name %}
       <h1 class="page-title">
         {{ site_name }}
@@ -23,12 +23,12 @@
   </header>
 
   {% if page.sidebar_first %}
-    <aside class="layout-sidebar-first" role="complementary">
+    <aside class="layout-sidebar-first">
       {{ page.sidebar_first }}
     </aside>{# /.layout-sidebar-first #}
   {% endif %}
 
-  <main role="main">
+  <main>
     {% if title %}
       <h1>{{ title }}</h1>
     {% endif %}
@@ -37,7 +37,7 @@
   </main>
 
   {% if page.sidebar_second %}
-    <aside class="layout-sidebar-second" role="complementary">
+    <aside class="layout-sidebar-second">
       {{ page.sidebar_second }}
     </aside>{# /.layout-sidebar-second #}
   {% endif %}
diff --git a/core/themes/seven/templates/maintenance-page.html.twig b/core/themes/seven/templates/maintenance-page.html.twig
index 2286e88..10dbcb7 100644
--- a/core/themes/seven/templates/maintenance-page.html.twig
+++ b/core/themes/seven/templates/maintenance-page.html.twig
@@ -11,19 +11,19 @@
 #}
 <div class="layout-container">
 
-  <header role="banner">
+  <header>
     {% if site_name %}
       <h1 class="page-title">{{ site_name }}</h1>
     {% endif %}
   </header>
 
   {% if page.sidebar_first %}
-    <aside class="layout-sidebar-first" role="complementary">
+    <aside class="layout-sidebar-first">
       {{ page.sidebar_first }}
     </aside>{# /.layout-sidebar-first #}
   {% endif %}
 
-  <main role="main">
+  <main>
     {% if title %}
       <h1>{{ title }}</h1>
     {% endif %}
diff --git a/core/themes/seven/templates/page.html.twig b/core/themes/seven/templates/page.html.twig
index 1a1a89b..6e678e8 100644
--- a/core/themes/seven/templates/page.html.twig
+++ b/core/themes/seven/templates/page.html.twig
@@ -48,7 +48,7 @@
   <div class="layout-container">
     {{ page.pre_content }}
     {{ page.breadcrumb }}
-    <main class="page-content clearfix" role="main">
+    <main class="page-content clearfix">
       <div class="visually-hidden"><a id="main-content" tabindex="-1"></a></div>
       {{ page.highlighted }}
       {% if page.help %}
diff --git a/core/themes/stable/templates/layout/install-page.html.twig b/core/themes/stable/templates/layout/install-page.html.twig
index 44341f4..b0ead3a 100644
--- a/core/themes/stable/templates/layout/install-page.html.twig
+++ b/core/themes/stable/templates/layout/install-page.html.twig
@@ -11,7 +11,7 @@
 #}
   <div class="layout-container">
 
-    <header role="banner">
+    <header>
       {% if site_name or site_slogan %}
         <div class="name-and-slogan">
           {% if site_name %}
@@ -24,7 +24,7 @@
       {% endif %}
     </header>
 
-    <main role="main">
+    <main>
       {% if title %}
         <h1>{{ title }}</h1>
       {% endif %}
@@ -33,13 +33,13 @@
     </main>
 
     {% if page.sidebar_first %}
-      <aside class="layout-sidebar-first" role="complementary">
+      <aside class="layout-sidebar-first">
         {{ page.sidebar_first }}
       </aside>{# /.layout-sidebar-first #}
     {% endif %}
 
     {% if page.sidebar_second %}
-      <aside class="layout-sidebar-second" role="complementary">
+      <aside class="layout-sidebar-second">
         {{ page.sidebar_second }}
       </aside>{# /.layout-sidebar-second #}
     {% endif %}
diff --git a/core/themes/stable/templates/layout/maintenance-page.html.twig b/core/themes/stable/templates/layout/maintenance-page.html.twig
index de0acaa..c127755 100644
--- a/core/themes/stable/templates/layout/maintenance-page.html.twig
+++ b/core/themes/stable/templates/layout/maintenance-page.html.twig
@@ -9,7 +9,7 @@
  * @see template_preprocess_maintenance_page()
  */
 #}
-<header role="banner">
+<header>
   {% if logo %}
     <a href="{{ front_page }}" title="{{ 'Home'|t }}" rel="home">
       <img src="{{ logo }}" alt="{{ 'Home'|t }}"/>
@@ -29,7 +29,7 @@
   {% endif %}
 </header>
 
-<main role="main">
+<main>
   {% if title %}
     <h1>{{ title }}</h1>
   {% endif %}
@@ -40,13 +40,13 @@
 </main>
 
 {% if page.sidebar_first %}
-  <aside role="complementary">
+  <aside>
     {{ page.sidebar_first }}
   </aside>
 {% endif %}
 
 {% if page.sidebar_second %}
-  <aside role="complementary">
+  <aside>
     {{ page.sidebar_second }}
   </aside>
 {% endif %}
diff --git a/core/themes/stable/templates/layout/page.html.twig b/core/themes/stable/templates/layout/page.html.twig
index 669a1c6..05ac4f6 100644
--- a/core/themes/stable/templates/layout/page.html.twig
+++ b/core/themes/stable/templates/layout/page.html.twig
@@ -45,7 +45,7 @@
 #}
 <div class="layout-container">
 
-  <header role="banner">
+  <header>
     {{ page.header }}
   </header>
 
@@ -58,7 +58,7 @@
 
   {{ page.help }}
 
-  <main role="main">
+  <main>
     <a id="main-content" tabindex="-1"></a>{# link is in html.html.twig #}
 
     <div class="layout-content">
@@ -66,13 +66,13 @@
     </div>{# /.layout-content #}
 
     {% if page.sidebar_first %}
-      <aside class="layout-sidebar-first" role="complementary">
+      <aside class="layout-sidebar-first">
         {{ page.sidebar_first }}
       </aside>
     {% endif %}
 
     {% if page.sidebar_second %}
-      <aside class="layout-sidebar-second" role="complementary">
+      <aside class="layout-sidebar-second">
         {{ page.sidebar_second }}
       </aside>
     {% endif %}