diff --git a/src/DefaultMetadataLoader.php b/src/DefaultMetadataLoader.php
index a79133490..c6b1f037c 100644
--- a/src/DefaultMetadataLoader.php
+++ b/src/DefaultMetadataLoader.php
@@ -2,6 +2,9 @@
 
 namespace libphonenumber;
 
+/**
+ * @internal
+ */
 class DefaultMetadataLoader implements MetadataLoaderInterface
 {
     public function loadMetadata($metadataFileName)
diff --git a/src/MetadataLoaderInterface.php b/src/MetadataLoaderInterface.php
index 8142027de..3ad0cf214 100644
--- a/src/MetadataLoaderInterface.php
+++ b/src/MetadataLoaderInterface.php
@@ -2,6 +2,9 @@
 
 namespace libphonenumber;
 
+/**
+ * @internal
+ */
 interface MetadataLoaderInterface
 {
     /**
diff --git a/src/PhoneNumberToTimeZonesMapper.php b/src/PhoneNumberToTimeZonesMapper.php
index 3cc5203a0..89da44488 100644
--- a/src/PhoneNumberToTimeZonesMapper.php
+++ b/src/PhoneNumberToTimeZonesMapper.php
@@ -29,7 +29,7 @@ class PhoneNumberToTimeZonesMapper
     protected function __construct($phonePrefixDataDirectory)
     {
         $this->prefixTimeZonesMap = static::loadPrefixTimeZonesMapFromFile(
-            \dirname(__FILE__) . $phonePrefixDataDirectory . DIRECTORY_SEPARATOR . static::MAPPING_DATA_FILE_NAME
+            __DIR__ . $phonePrefixDataDirectory . DIRECTORY_SEPARATOR . static::MAPPING_DATA_FILE_NAME
         );
         $this->phoneUtil = PhoneNumberUtil::getInstance();
 
diff --git a/src/prefixmapper/PrefixFileReader.php b/src/prefixmapper/PrefixFileReader.php
index bda340a34..72865b4c1 100644
--- a/src/prefixmapper/PrefixFileReader.php
+++ b/src/prefixmapper/PrefixFileReader.php
@@ -9,6 +9,7 @@
  * A helper class doing file handling and lookup of phone number prefix mappings.
  *
  * @package libphonenumber\prefixmapper
+ * @internal
  */
 class PrefixFileReader
 {