Initial Drupal 11 with DDEV setup

web/core/modules/locale/js/locale.bulk.js

@@ -0,0 +1,37 @@
+/**
+ * @file
+ * Locale behavior.
+ */
+
+(function ($, Drupal) {
+  /**
+   * Select the language code of an imported file based on its filename.
+   *
+   * This only works if the file name ends with "LANGCODE.po".
+   *
+   * @type {Drupal~behavior}
+   *
+   * @prop {Drupal~behaviorAttach} attach
+   *   Attaches behavior for preselecting language code based on filename.
+   */
+  Drupal.behaviors.importLanguageCodeSelector = {
+    attach(context, settings) {
+      const form = once('autodetect-lang', '#locale-translate-import-form');
+      if (form.length) {
+        const $form = $(form);
+        const $langcode = $form.find('.langcode-input');
+        $form.find('.file-import-input').on('change', function () {
+          // If the filename is fully the language code or the filename
+          // ends with a language code, pre-select that one.
+          const matches = this.value.match(/([^.][.]*)([\w-]+)\.po$/);
+          if (
+            matches &&
+            $langcode.find(`option[value="${matches[2]}"]`).length
+          ) {
+            $langcode[0].value = matches[2];
+          }
+        });
+      }
+    },
+  };
+})(jQuery, Drupal);