Issue #3496002: Update Translation Edit Form labels to use human friendly Labels

string_plural_form.module

+<?php
+
+/**
+ * @file
+ * String Plural Form Module file.
+ */
+
+use Drupal\Core\Render\Element;
+
+/**
+ * Implements hook_form_FORM_ID_alter().
+ */
+function string_plural_form_form_locale_translate_edit_form_alter(&$form, $form_state) {
+  if (isset($form['strings'])) {
+    $config = \Drupal::config('string_plural_form.settings')
+      ->get('rules');
+    $lang_code = $form["langcode"]["#value"];
+    if (empty($config[$lang_code])) {
+      return;
+    }
+    $instance = \Drupal::service('plugin.manager.string_plural_form')->createInstance($config[$lang_code]);
+    foreach (Element::children($form['strings']) as $key) {
+      $item = &$form['strings'][$key];
+      if (isset($item['translations'][1])) {
+        foreach (Element::children($item['translations']) as $index) {
+          $form['strings'][$key]['translations'][$index]['#title'] = $instance->getIndexLabel($index);
+        }
+      }
+    }
+  }
+}