Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

core/themes/seven/templates/install-page.html.twig

@@ -13,7 +13,12 @@
 
   <header role="banner">
     {% if site_name %}
-      <h1 class="page-title">{{ site_name }}</h1>
+      <h1 class="page-title">
+        {{ site_name }}
+        {% if site_version %}
+          <span class="site-version">{{ site_version }}</span>
+        {% endif %}
+      </h1>
     {% endif %}
   </header>
 

core/themes/seven/templates/page.html.twig

@@ -27,11 +27,6 @@
  *   slogan has been disabled in theme settings.
  *
  * Page content (in order of occurrence in the default page.html.twig):
- * - title_prefix: Additional output populated by modules, intended to be
- *   displayed in front of the main title tag that appears in the template.
- * - title: The page title, for use in the actual content.
- * - title_suffix: Additional output populated by modules, intended to be
- *   displayed after the main title tag that appears in the template.
  * - node: Fully loaded node, if there is an automatically-loaded node
  *   associated with the page and the node ID is the second argument in the
  *   page's path (e.g. node/12345 and node/12345/revisions, but not
@@ -52,11 +47,6 @@
 #}
   <header class="content-header clearfix">
     <div class="layout-container">
-      {{ title_prefix }}
-      {% if title %}
-        <h1 class="page-title">{{ title }}</h1>
-      {% endif %}
-      {{ title_suffix }}
       {{ page.header }}
     </div>
   </header>

core/themes/seven/templates/tablesort-indicator.html.twig

@@ -1,16 +0,0 @@
-{#
-/**
- * @file
- * Seven's theme implementation for displaying a tablesort indicator.
- *
- * Available variables:
- * - style: Either 'asc' or 'desc', indicating the sorting direction.
- * - arrow_asc: URL to the image for an ascending arrow.
- * - arrow_desc: URL to the image for a descending arrow.
- */
-#}
-{% if style == 'asc' -%}
-  <img src="{{ arrow_asc }}" width="9" height="5" alt="{{ 'Sort ascending'|t }}" title="{{ 'Sort ascending'|t }}" />
-{% else -%}
-  <img src="{{ arrow_desc }}" width="9" height="5" alt="{{ 'Sort descending'|t }}" title="{{ 'Sort descending'|t }}" />
-{% endif %}