--- /dev/null
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\filefield_sources\FilefieldSourcesServiceProvider.
+ */
+
+namespace Drupal\filefield_sources;
+
+use Drupal\Core\DependencyInjection\ServiceModifierInterface;
+use Drupal\Core\DependencyInjection\ContainerBuilder;
+
+/**
+ * Alter file.mime_type.guesser.extension service.
+ */
+class FilefieldSourcesServiceProvider implements ServiceModifierInterface {
+
+ /**
+ * {@inheritdoc}
+ */
+ public function alter(ContainerBuilder $container) {
+ $definition = $container->getDefinition('file.mime_type.guesser.extension');
+ $definition->setClass('Drupal\filefield_sources\File\MimeType\ExtensionMimeTypeGuesser');
+ }
+
+}