Update to Drupal 8.2.0. For more information, see https://www.drupal.org/project/drupal/releases/8.2.0

core/modules/contextual/contextual.module

@@ -35,7 +35,6 @@ function contextual_toolbar() {
       '#value' => t('Edit'),
       '#attributes' => array(
         'class' => array('toolbar-icon', 'toolbar-icon-edit'),
-        'role' => 'button',
         'aria-pressed' => 'false',
       ),
     ),

core/modules/contextual/contextual.permissions.yml

@@ -1,3 +1,2 @@
 access contextual links:
   title: 'Use contextual links'
-  description: 'Use contextual links to perform actions related to elements on a page.'

core/modules/contextual/contextual.routing.yml

@@ -2,7 +2,5 @@ contextual.render:
   path: '/contextual/render'
   defaults:
     _controller: '\Drupal\contextual\ContextualController::render'
-  options:
-    _theme: ajax_base_page
   requirements:
     _permission: 'access contextual links'