diff --git a/gio/giomodule.c b/gio/giomodule.c
index 1ead84c..8c2a464 100644
--- a/gio/giomodule.c
+++ b/gio/giomodule.c
@@ -1136,6 +1136,7 @@ _g_io_modules_ensure_loaded (void)
       /* Initialize types from built-in "modules" */
       g_type_ensure (g_null_settings_backend_get_type ());
       g_type_ensure (g_memory_settings_backend_get_type ());
+      g_type_ensure (g_keyfile_settings_backend_get_type ());
 #if defined(HAVE_INOTIFY_INIT1)
       g_type_ensure (g_inotify_file_monitor_get_type ());
 #endif
diff --git a/gio/gkeyfilesettingsbackend.c b/gio/gkeyfilesettingsbackend.c
index a37978e..f535881 100644
--- a/gio/gkeyfilesettingsbackend.c
+++ b/gio/gkeyfilesettingsbackend.c
@@ -21,14 +21,20 @@
 
 #include "config.h"
 
+#include <glib.h>
+#include <glibintl.h>
+
 #include <stdio.h>
 #include <string.h>
 
 #include "gfile.h"
 #include "gfileinfo.h"
+#include "gfileenumerator.h"
 #include "gfilemonitor.h"
 #include "gsimplepermission.h"
-#include "gsettingsbackend.h"
+#include "gsettingsbackendinternal.h"
+#include "giomodule-priv.h"
+#include "gportalsupport.h"
 
 
 #define G_TYPE_KEYFILE_SETTINGS_BACKEND      (g_keyfile_settings_backend_get_type ())
@@ -41,6 +47,13 @@
 
 typedef GSettingsBackendClass GKeyfileSettingsBackendClass;
 
+typedef enum {
+  PROP_FILENAME = 1,
+  PROP_ROOT_PATH,
+  PROP_ROOT_GROUP,
+  PROP_DEFAULTS_DIR
+} GKeyfileSettingsBackendProperty;
+
 typedef struct
 {
   GSettingsBackend   parent_instance;
@@ -48,6 +61,9 @@ typedef struct
   GKeyFile          *keyfile;
   GPermission       *permission;
   gboolean           writable;
+  char              *defaults_dir;
+  GKeyFile          *system_keyfile;
+  GHashTable        *system_locks; /* Used as a set, owning the strings it contains */
 
   gchar             *prefix;
   gint               prefix_len;
@@ -61,10 +77,18 @@ typedef struct
   GFileMonitor      *dir_monitor;
 } GKeyfileSettingsBackend;
 
-static GType g_keyfile_settings_backend_get_type (void);
-G_DEFINE_TYPE (GKeyfileSettingsBackend,
-               g_keyfile_settings_backend,
-               G_TYPE_SETTINGS_BACKEND)
+#ifdef G_OS_WIN32
+#define EXTENSION_PRIORITY 10
+#else
+#define EXTENSION_PRIORITY (glib_should_use_portal () && !glib_has_dconf_access_in_sandbox () ? 110 : 10)
+#endif
+
+G_DEFINE_TYPE_WITH_CODE (GKeyfileSettingsBackend,
+                         g_keyfile_settings_backend,
+                         G_TYPE_SETTINGS_BACKEND,
+                         _g_io_modules_ensure_extension_points_registered ();
+                         g_io_extension_point_implement (G_SETTINGS_BACKEND_EXTENSION_POINT_NAME,
+                                                         g_define_type_id, "keyfile", EXTENSION_PRIORITY))
 
 static void
 compute_checksum (guint8        *digest,
@@ -184,17 +208,51 @@ get_from_keyfile (GKeyfileSettingsBackend *kfsb,
   if (convert_path (kfsb, key, &group, &name))
     {
       gchar *str;
+      gchar *sysstr;
 
       g_assert (*name);
 
+      sysstr = g_key_file_get_value (kfsb->system_keyfile, group, name, NULL);
       str = g_key_file_get_value (kfsb->keyfile, group, name, NULL);
+      if (sysstr &&
+          (g_hash_table_contains (kfsb->system_locks, key) ||
+           str == NULL))
+        {
+          g_free (str);
+          str = g_steal_pointer (&sysstr);
+        }
 
       if (str)
         {
           return_value = g_variant_parse (type, str, NULL, NULL, NULL);
+
+          /* As a special case, support values of type %G_VARIANT_TYPE_STRING
+           * not being quoted, since users keep forgetting to do it and then
+           * getting confused. */
+          if (return_value == NULL &&
+              g_variant_type_equal (type, G_VARIANT_TYPE_STRING) &&
+              str[0] != '\"')
+            {
+              GString *s = g_string_sized_new (strlen (str) + 2);
+              char *p = str;
+
+              g_string_append_c (s, '\"');
+              while (*p)
+                {
+                  if (*p == '\"')
+                    g_string_append_c (s, '\\');
+                  g_string_append_c (s, *p);
+                  p++;
+                }
+              g_string_append_c (s, '\"');
+              return_value = g_variant_parse (type, s->str, NULL, NULL, NULL);
+              g_string_free (s, TRUE);
+            }
           g_free (str);
         }
 
+      g_free (sysstr);
+
       g_free (group);
       g_free (name);
     }
@@ -209,6 +267,9 @@ set_to_keyfile (GKeyfileSettingsBackend *kfsb,
 {
   gchar *group, *name;
 
+  if (g_hash_table_contains (kfsb->system_locks, key))
+    return FALSE;
+
   if (convert_path (kfsb, key, &group, &name))
     {
       if (value)
@@ -287,7 +348,8 @@ g_keyfile_settings_backend_check_one (gpointer key,
 {
   WriteManyData *data = user_data;
 
-  return data->failed = !path_is_valid (data->kfsb, key);
+  return data->failed = g_hash_table_contains (data->kfsb->system_locks, key) ||
+                        !path_is_valid (data->kfsb, key);
 }
 
 static gboolean
@@ -355,7 +417,9 @@ g_keyfile_settings_backend_get_writable (GSettingsBackend *backend,
 {
   GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
 
-  return kfsb->writable && path_is_valid (kfsb, name);
+  return kfsb->writable &&
+         !g_hash_table_contains (kfsb->system_locks, name) &&
+         path_is_valid (kfsb, name);
 }
 
 static GPermission *
@@ -501,6 +565,9 @@ g_keyfile_settings_backend_finalize (GObject *object)
 
   g_key_file_free (kfsb->keyfile);
   g_object_unref (kfsb->permission);
+  g_key_file_unref (kfsb->system_keyfile);
+  g_hash_table_unref (kfsb->system_locks);
+  g_free (kfsb->defaults_dir);
 
   g_file_monitor_cancel (kfsb->file_monitor);
   g_object_unref (kfsb->file_monitor);
@@ -523,25 +590,6 @@ g_keyfile_settings_backend_init (GKeyfileSettingsBackend *kfsb)
 }
 
 static void
-g_keyfile_settings_backend_class_init (GKeyfileSettingsBackendClass *class)
-{
-  GObjectClass *object_class = G_OBJECT_CLASS (class);
-
-  object_class->finalize = g_keyfile_settings_backend_finalize;
-
-  class->read = g_keyfile_settings_backend_read;
-  class->write = g_keyfile_settings_backend_write;
-  class->write_tree = g_keyfile_settings_backend_write_tree;
-  class->reset = g_keyfile_settings_backend_reset;
-  class->get_writable = g_keyfile_settings_backend_get_writable;
-  class->get_permission = g_keyfile_settings_backend_get_permission;
-  /* No need to implement subscribed/unsubscribe: the only point would be to
-   * stop monitoring the file when there's no GSettings anymore, which is no
-   * big win.
-   */
-}
-
-static void
 file_changed (GFileMonitor      *monitor,
               GFile             *file,
               GFile             *other_file,
@@ -567,6 +615,283 @@ dir_changed (GFileMonitor       *monitor,
   g_keyfile_settings_backend_keyfile_writable (kfsb);
 }
 
+static void
+load_system_settings (GKeyfileSettingsBackend *kfsb)
+{
+  GError *error = NULL;
+  const char *dir = "/etc/glib-2.0/settings";
+  char *path;
+  char *contents;
+
+  kfsb->system_keyfile = g_key_file_new ();
+  kfsb->system_locks = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
+
+  if (kfsb->defaults_dir)
+    dir = kfsb->defaults_dir;
+
+  path = g_build_filename (dir, "defaults", NULL);
+
+  /* The defaults are in the same keyfile format that we use for the settings.
+   * It can be produced from a dconf database using: dconf dump
+   */
+  if (!g_key_file_load_from_file (kfsb->system_keyfile, path, G_KEY_FILE_NONE, &error))
+    {
+      if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
+        g_warning ("Failed to read %s: %s", path, error->message);
+      g_clear_error (&error);
+    }
+  else
+    g_debug ("Loading default settings from %s", path);
+
+  g_free (path);
+
+  path = g_build_filename (dir, "locks", NULL);
+
+  /* The locks file is a text file containing a list paths to lock, one per line.
+   * It can be produced from a dconf database using: dconf list-locks
+   */
+  if (!g_file_get_contents (path, &contents, NULL, &error))
+    {
+      if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
+        g_warning ("Failed to read %s: %s", path, error->message);
+      g_clear_error (&error);
+    }
+  else
+    {
+      char **lines;
+      gsize i;
+
+      g_debug ("Loading locks from %s", path);
+
+      lines = g_strsplit (contents, "\n", 0);
+      for (i = 0; lines[i]; i++)
+        {
+          char *line = lines[i];
+          if (line[0] == '#' || line[0] == '\0')
+            {
+              g_free (line);
+              continue;
+            }
+
+          g_debug ("Locking key %s", line);
+          g_hash_table_add (kfsb->system_locks, g_steal_pointer (&line));
+        }
+
+      g_free (lines);
+    }
+  g_free (contents);
+
+  g_free (path);
+}
+
+static void
+g_keyfile_settings_backend_constructed (GObject *object)
+{
+  GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (object);
+
+  if (kfsb->file == NULL)
+    {
+      char *filename = g_build_filename (g_get_user_config_dir (),
+                                         "glib-2.0", "settings", "keyfile",
+                                         NULL);
+      kfsb->file = g_file_new_for_path (filename);
+      g_free (filename);
+    }
+
+  if (kfsb->prefix == NULL)
+    {
+      kfsb->prefix = g_strdup ("/");
+      kfsb->prefix_len = 1;
+    }
+  
+  kfsb->keyfile = g_key_file_new ();
+  kfsb->permission = g_simple_permission_new (TRUE);
+
+  kfsb->dir = g_file_get_parent (kfsb->file);
+  g_file_make_directory_with_parents (kfsb->dir, NULL, NULL);
+
+  kfsb->file_monitor = g_file_monitor (kfsb->file, G_FILE_MONITOR_NONE, NULL, NULL);
+  kfsb->dir_monitor = g_file_monitor (kfsb->dir, G_FILE_MONITOR_NONE, NULL, NULL);
+
+  compute_checksum (kfsb->digest, NULL, 0);
+
+  g_signal_connect (kfsb->file_monitor, "changed",
+                    G_CALLBACK (file_changed), kfsb);
+  g_signal_connect (kfsb->dir_monitor, "changed",
+                    G_CALLBACK (dir_changed), kfsb);
+
+  g_keyfile_settings_backend_keyfile_writable (kfsb);
+  g_keyfile_settings_backend_keyfile_reload (kfsb);
+
+  load_system_settings (kfsb);
+}
+
+static void
+g_keyfile_settings_backend_set_property (GObject      *object,
+                                         guint         prop_id,
+                                         const GValue *value,
+                                         GParamSpec   *pspec)
+{
+  GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (object);
+
+  switch ((GKeyfileSettingsBackendProperty)prop_id)
+    {
+    case PROP_FILENAME:
+      /* Construct only. */
+      g_assert (kfsb->file == NULL);
+      if (g_value_get_string (value))
+        kfsb->file = g_file_new_for_path (g_value_get_string (value));
+      break;
+
+    case PROP_ROOT_PATH:
+      /* Construct only. */
+      g_assert (kfsb->prefix == NULL);
+      kfsb->prefix = g_value_dup_string (value);
+      if (kfsb->prefix)
+        kfsb->prefix_len = strlen (kfsb->prefix);
+      break;
+
+    case PROP_ROOT_GROUP:
+      /* Construct only. */
+      g_assert (kfsb->root_group == NULL);
+      kfsb->root_group = g_value_dup_string (value);
+      if (kfsb->root_group)
+        kfsb->root_group_len = strlen (kfsb->root_group);
+      break;
+
+    case PROP_DEFAULTS_DIR:
+      /* Construct only. */
+      g_assert (kfsb->defaults_dir == NULL);
+      kfsb->defaults_dir = g_value_dup_string (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+g_keyfile_settings_backend_get_property (GObject    *object,
+                                         guint       prop_id,
+                                         GValue     *value,
+                                         GParamSpec *pspec)
+{
+  GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (object);
+
+  switch ((GKeyfileSettingsBackendProperty)prop_id)
+    {
+    case PROP_FILENAME:
+      g_value_set_string (value, g_file_peek_path (kfsb->file));
+      break;
+
+    case PROP_ROOT_PATH:
+      g_value_set_string (value, kfsb->prefix);
+      break;
+
+    case PROP_ROOT_GROUP:
+      g_value_set_string (value, kfsb->root_group);
+      break;
+
+    case PROP_DEFAULTS_DIR:
+      g_value_set_string (value, kfsb->defaults_dir);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+g_keyfile_settings_backend_class_init (GKeyfileSettingsBackendClass *class)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+
+  object_class->finalize = g_keyfile_settings_backend_finalize;
+  object_class->constructed = g_keyfile_settings_backend_constructed;
+  object_class->get_property = g_keyfile_settings_backend_get_property;
+  object_class->set_property = g_keyfile_settings_backend_set_property;
+
+  class->read = g_keyfile_settings_backend_read;
+  class->write = g_keyfile_settings_backend_write;
+  class->write_tree = g_keyfile_settings_backend_write_tree;
+  class->reset = g_keyfile_settings_backend_reset;
+  class->get_writable = g_keyfile_settings_backend_get_writable;
+  class->get_permission = g_keyfile_settings_backend_get_permission;
+  /* No need to implement subscribed/unsubscribe: the only point would be to
+   * stop monitoring the file when there's no GSettings anymore, which is no
+   * big win.
+   */
+
+  /**
+   * GKeyfileSettingsBackend:filename:
+   *
+   * The location where the settings are stored on disk.
+   *
+   * Defaults to `$XDG_CONFIG_HOME/glib-2.0/settings/keyfile`.
+   */
+  g_object_class_install_property (object_class,
+                                   PROP_FILENAME,
+                                   g_param_spec_string ("filename",
+                                                        P_("Filename"),
+                                                        P_("The filename"),
+                                                        NULL,
+                                                        G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
+                                                        G_PARAM_STATIC_STRINGS));
+
+  /**
+   * GKeyfileSettingsBackend:root-path:
+   *
+   * All settings read to or written from the backend must fall under the
+   * path given in @root_path (which must start and end with a slash and
+   * not contain two consecutive slashes).  @root_path may be "/".
+   * 
+   * Defaults to "/".
+   */
+  g_object_class_install_property (object_class,
+                                   PROP_ROOT_PATH,
+                                   g_param_spec_string ("root-path",
+                                                        P_("Root path"),
+                                                        P_("The root path"),
+                                                        NULL,
+                                                        G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
+                                                        G_PARAM_STATIC_STRINGS));
+
+  /**
+   * GKeyfileSettingsBackend:root-group:
+   *
+   * If @root_group is non-%NULL then it specifies the name of the keyfile
+   * group used for keys that are written directly below the root path.
+   *
+   * Defaults to NULL.
+   */
+  g_object_class_install_property (object_class,
+                                   PROP_ROOT_GROUP,
+                                   g_param_spec_string ("root-group",
+                                                        P_("Root group"),
+                                                        P_("The root group"),
+                                                        NULL,
+                                                        G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
+                                                        G_PARAM_STATIC_STRINGS));
+
+  /**
+   * GKeyfileSettingsBackend:default-dir:
+   *
+   * The directory where the system defaults and locks are located.
+   *
+   * Defaults to `/etc/glib-2.0/settings`.
+   */
+  g_object_class_install_property (object_class,
+                                   PROP_DEFAULTS_DIR,
+                                   g_param_spec_string ("defaults-dir",
+                                                        P_("Default dir"),
+                                                        P_("Defaults dir"),
+                                                        NULL,
+                                                        G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
+                                                        G_PARAM_STATIC_STRINGS));
+}
+
 /**
  * g_keyfile_settings_backend_new:
  * @filename: the filename of the keyfile
@@ -619,6 +944,11 @@ dir_changed (GFileMonitor       *monitor,
  * characters in your path names or '=' in your key names you may be in
  * trouble.
  *
+ * The backend reads default values from a keyfile called `defaults` in
+ * the directory specified by the #GKeyfileSettingsBackend:defaults-dir property,
+ * and a list of locked keys from a text file with the name `locks` in
+ * the same location.
+ *
  * Returns: (transfer full): a keyfile-backed #GSettingsBackend
  **/
 GSettingsBackend *
@@ -626,43 +956,15 @@ g_keyfile_settings_backend_new (const gchar *filename,
                                 const gchar *root_path,
                                 const gchar *root_group)
 {
-  GKeyfileSettingsBackend *kfsb;
-
   g_return_val_if_fail (filename != NULL, NULL);
   g_return_val_if_fail (root_path != NULL, NULL);
   g_return_val_if_fail (g_str_has_prefix (root_path, "/"), NULL);
   g_return_val_if_fail (g_str_has_suffix (root_path, "/"), NULL);
   g_return_val_if_fail (strstr (root_path, "//") == NULL, NULL);
 
-  kfsb = g_object_new (G_TYPE_KEYFILE_SETTINGS_BACKEND, NULL);
-  kfsb->keyfile = g_key_file_new ();
-  kfsb->permission = g_simple_permission_new (TRUE);
-
-  kfsb->file = g_file_new_for_path (filename);
-  kfsb->dir = g_file_get_parent (kfsb->file);
-  g_file_make_directory_with_parents (kfsb->dir, NULL, NULL);
-
-  kfsb->file_monitor = g_file_monitor (kfsb->file, 0, NULL, NULL);
-  kfsb->dir_monitor = g_file_monitor (kfsb->dir, 0, NULL, NULL);
-
-  kfsb->prefix_len = strlen (root_path);
-  kfsb->prefix = g_strdup (root_path);
-
-  if (root_group)
-    {
-      kfsb->root_group_len = strlen (root_group);
-      kfsb->root_group = g_strdup (root_group);
-    }
-
-  compute_checksum (kfsb->digest, NULL, 0);
-
-  g_signal_connect (kfsb->file_monitor, "changed",
-                    G_CALLBACK (file_changed), kfsb);
-  g_signal_connect (kfsb->dir_monitor, "changed",
-                    G_CALLBACK (dir_changed), kfsb);
-
-  g_keyfile_settings_backend_keyfile_writable (kfsb);
-  g_keyfile_settings_backend_keyfile_reload (kfsb);
-
-  return G_SETTINGS_BACKEND (kfsb);
+  return G_SETTINGS_BACKEND (g_object_new (G_TYPE_KEYFILE_SETTINGS_BACKEND,
+                                           "filename", filename,
+                                           "root-path", root_path,
+                                           "root-group", root_group,
+                                           NULL));
 }
diff --git a/gio/gportalsupport.c b/gio/gportalsupport.c
index 2f1e825..b0a94b3 100644
--- a/gio/gportalsupport.c
+++ b/gio/gportalsupport.c
@@ -23,6 +23,7 @@
 static gboolean flatpak_info_read;
 static gboolean use_portal;
 static gboolean network_available;
+static gboolean dconf_access;
 
 static void
 read_flatpak_info (void)
@@ -40,11 +41,13 @@ read_flatpak_info (void)
 
       use_portal = TRUE;
       network_available = FALSE;
+      dconf_access = FALSE;
 
       keyfile = g_key_file_new ();
       if (g_key_file_load_from_file (keyfile, path, G_KEY_FILE_NONE, NULL))
         {
           char **shared = NULL;
+          char *dconf_policy = NULL;
 
           shared = g_key_file_get_string_list (keyfile, "Context", "shared", NULL, NULL);
           if (shared)
@@ -52,6 +55,14 @@ read_flatpak_info (void)
               network_available = g_strv_contains ((const char * const *)shared, "network");
               g_strfreev (shared);
             }
+
+          dconf_policy = g_key_file_get_string (keyfile, "Session Bus Policy", "ca.desrt.dconf", NULL);
+          if (dconf_policy)
+            {
+              if (strcmp (dconf_policy, "talk") == 0)
+                dconf_access = TRUE;
+              g_free (dconf_policy);
+            }
         }
 
       g_key_file_unref (keyfile);
@@ -64,6 +75,7 @@ read_flatpak_info (void)
       if (var && var[0] == '1')
         use_portal = TRUE;
       network_available = TRUE;
+      dconf_access = TRUE;
     }
 }
 
@@ -81,3 +93,9 @@ glib_network_available_in_sandbox (void)
   return network_available;
 }
 
+gboolean
+glib_has_dconf_access_in_sandbox (void)
+{
+  read_flatpak_info ();
+  return dconf_access;
+}
diff --git a/gio/gportalsupport.h b/gio/gportalsupport.h
index a331f45..746f1fd 100644
--- a/gio/gportalsupport.h
+++ b/gio/gportalsupport.h
@@ -24,6 +24,7 @@ G_BEGIN_DECLS
 
 gboolean glib_should_use_portal (void);
 gboolean glib_network_available_in_sandbox (void);
+gboolean glib_has_dconf_access_in_sandbox (void);
 
 G_END_DECLS
 
diff --git a/gio/gsettingsbackendinternal.h b/gio/gsettingsbackendinternal.h
index 2a76a80..9e1d51d 100644
--- a/gio/gsettingsbackendinternal.h
+++ b/gio/gsettingsbackendinternal.h
@@ -87,6 +87,8 @@ GType                   g_null_settings_backend_get_type                (void);
 
 GType                   g_memory_settings_backend_get_type              (void);
 
+GType                   g_keyfile_settings_backend_get_type             (void);
+
 #ifdef HAVE_COCOA
 GType                   g_nextstep_settings_backend_get_type            (void);
 #endif
diff --git a/gio/tests/gsettings.c b/gio/tests/gsettings.c
index acdeead..65c6074 100644
--- a/gio/tests/gsettings.c
+++ b/gio/tests/gsettings.c
@@ -1716,6 +1716,23 @@ test_keyfile (void)
   g_assert_cmpstr (str, ==, "howdy");
   g_free (str);
 
+  /* Now check setting a string without quotes */
+  called = FALSE;
+  g_signal_connect (settings, "changed::greeting", G_CALLBACK (key_changed_cb), &called);
+
+  g_key_file_set_string (keyfile, "tests", "greeting", "he\"l🤗uń");
+  g_free (data);
+  data = g_key_file_to_data (keyfile, &len, NULL);
+  g_file_set_contents ("keyfile/gsettings.store", data, len, &error);
+  g_assert_no_error (error);
+  while (!called)
+    g_main_context_iteration (NULL, FALSE);
+  g_signal_handlers_disconnect_by_func (settings, key_changed_cb, &called);
+
+  str = g_settings_get_string (settings, "greeting");
+  g_assert_cmpstr (str, ==, "he\"l🤗uń");
+  g_free (str);
+
   g_settings_set (settings, "farewell", "s", "cheerio");
   
   called = FALSE;