Index: wp-includes/post.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- wp-includes/post.php	(revision 7696b79d0caf7d16f2407070bc6c47c2edf80042)
+++ wp-includes/post.php	(revision )
@@ -1826,7 +1826,20 @@
  *               field if $single is true.
  */
 function get_post_meta( $post_id, $key = '', $single = false ) {
-	return get_metadata('post', $post_id, $key, $single);
+	/**
+	 * Filter the meta value.
+	 *
+	 * @since 4.5.0
+	 *
+	 * @param mixed  $value   Value of the post meta value.
+	 * @param int    $post_id Post ID.
+	 * @param string $key     The meta key to retrieve. By default, returns
+	 *                        data for all keys.
+	 * @param bool   $single  Whether to return a single value.
+	 * @return mixed Will be an array if $single is false. Will be value of meta data
+	 *               field if $single is true.
+	 */
+	return apply_filters( 'post_meta', get_metadata( 'post', $post_id, $key, $single ), $post_id, $key, $single );
 }
 
 /**