See #54729 Built from https://develop.svn.wordpress.org/trunk@53316 git-svn-id: http://core.svn.wordpress.org/trunk@52905 1a063a9b-81f0-0310-95a4-ce76da25c4cd
$manager
/
$type
$mime_type
$button_labels
WP_Customize_Upload_Control