Index: src/wp-includes/functions.php
===================================================================
--- src/wp-includes/functions.php	(revision 44226)
+++ src/wp-includes/functions.php	(working copy)
@@ -2512,6 +2512,7 @@
 	'wax' => 'audio/x-ms-wax',
 	'mka' => 'audio/x-matroska',
 	// Misc application formats.
+	'json' =>'application/json',
 	'rtf' => 'application/rtf',
 	'js' => 'application/javascript',
 	'pdf' => 'application/pdf',