Source

File: wp-admin/includes/post.php

function wp_edit_attachments_query( $q = false ) {
	wp( wp_edit_attachments_query_vars( $q ) );

	$post_mime_types       = get_post_mime_types();
	$avail_post_mime_types = get_available_post_mime_types( 'attachment' );

	return array( $post_mime_types, $avail_post_mime_types );
}