--- /dev/null
+<?php
+
+namespace Drupal\language\Config;
+
+use Drupal\Core\Config\ConfigFactoryOverrideInterface;
+use Drupal\Core\Language\LanguageInterface;
+use Drupal\Core\Language\LanguageDefault;
+
+/**
+ * Defines the interface for a configuration factory language override object.
+ */
+interface LanguageConfigFactoryOverrideInterface extends ConfigFactoryOverrideInterface {
+
+ /**
+ * Gets the language object used to override configuration data.
+ *
+ * @return \Drupal\Core\Language\LanguageInterface
+ * The language object used to override configuration data.
+ */
+ public function getLanguage();
+
+ /**
+ * Sets the language to be used in configuration overrides.
+ *
+ * @param \Drupal\Core\Language\LanguageInterface $language
+ * The language object used to override configuration data.
+ *
+ * @return $this
+ */
+ public function setLanguage(LanguageInterface $language = NULL);
+
+ /**
+ * Sets the language to be used in configuration overrides from the default.
+ *
+ * @param \Drupal\Core\Language\LanguageDefault $language_default
+ * The default language.
+ *
+ * @return $this
+ *
+ * @deprecated in Drupal 8.3.x and will be removed before Drupal 9.0.0. This
+ * method has been replaced by injecting the default language into the
+ * constructor.
+ */
+ public function setLanguageFromDefault(LanguageDefault $language_default = NULL);
+
+ /**
+ * Get language override for given language and configuration name.
+ *
+ * @param string $langcode
+ * Language code.
+ * @param string $name
+ * Configuration name.
+ *
+ * @return \Drupal\Core\Config\Config
+ * Configuration override object.
+ */
+ public function getOverride($langcode, $name);
+
+ /**
+ * Returns the storage instance for a particular langcode.
+ *
+ * @param string $langcode
+ * Language code.
+ *
+ * @return \Drupal\Core\Config\StorageInterface
+ * The storage instance for a particular langcode.
+ */
+ public function getStorage($langcode);
+
+ /**
+ * Installs available language configuration overrides for a given langcode.
+ *
+ * @param string $langcode
+ * Language code.
+ */
+ public function installLanguageOverrides($langcode);
+
+}