diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index b150598d27..b011702f74 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -2019,7 +2019,7 @@ function wp_ext2type( $ext ) {
 		'image'       => array( 'jpg', 'jpeg', 'jpe',  'gif',  'png',  'bmp',   'tif',  'tiff', 'ico' ),
 		'audio'       => array( 'aac', 'ac3',  'aif',  'aiff', 'm3a',  'm4a',   'm4b',  'mka',  'mp1',  'mp2',  'mp3', 'ogg', 'oga', 'ram', 'wav', 'wma' ),
 		'video'       => array( '3g2',  '3gp', '3gpp', 'asf', 'avi',  'divx', 'dv',   'flv',  'm4v',   'mkv',  'mov',  'mp4',  'mpeg', 'mpg', 'mpv', 'ogm', 'ogv', 'qt',  'rm', 'vob', 'wmv' ),
-		'document'    => array( 'doc', 'docx', 'docm', 'dotm', 'odt',  'pages', 'pdf',  'xps',  'oxps', 'rtf',  'wp', 'wpd', 'psd' ),
+		'document'    => array( 'doc', 'docx', 'docm', 'dotm', 'odt',  'pages', 'pdf',  'xps',  'oxps', 'rtf',  'wp', 'wpd', 'psd', 'xcf' ),
 		'spreadsheet' => array( 'numbers',     'ods',  'xls',  'xlsx', 'xlsm',  'xlsb' ),
 		'interactive' => array( 'swf', 'key',  'ppt',  'pptx', 'pptm', 'pps',   'ppsx', 'ppsm', 'sldx', 'sldm', 'odp' ),
 		'text'        => array( 'asc', 'csv',  'tsv',  'txt' ),
@@ -2227,6 +2227,7 @@ function wp_get_mime_types() {
 	'7z' => 'application/x-7z-compressed',
 	'exe' => 'application/x-msdownload',
 	'psd' => 'application/octet-stream',
+	'xcf' => 'application/octet-stream',
 	// MS Office formats.
 	'doc' => 'application/msword',
 	'pot|pps|ppt' => 'application/vnd.ms-powerpoint',
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 9ac361e672..03d2a1daf8 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31577';
+$wp_version = '4.2-alpha-31578';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.