Index: wp-includes/http.php
===================================================================
--- wp-includes/http.php	(revision 25263)
+++ wp-includes/http.php	(working copy)
@@ -338,6 +338,12 @@
 	if ( ! empty ( $_SERVER[ 'HTTP_ORIGIN' ] ) )
 		$origin = $_SERVER[ 'HTTP_ORIGIN' ];
 
+	/**
+	 * Change the origin of an HTTP requestion.
+	 *
+	 * @since  3.4.0
+	 * @param string $origin The original origin for the request
+	 */
 	return apply_filters( 'http_origin', $origin );
 }
 
@@ -360,6 +366,12 @@
 		'https://' . $home_origin[ 'host' ],
 	) );
 
+	/**
+	 * Change the origin types allowed for http requests.
+	 *
+	 * @since  3.4.0
+	 * @param  array $allowed_origins Default allowed http origins.
+	 */
 	return apply_filters( 'allowed_http_origins' , $allowed_origins );
 }
 
@@ -380,6 +392,13 @@
 	if ( $origin && ! in_array( $origin, get_allowed_http_origins() ) )
 		$origin = '';
 
+	/**
+	 * Change the allowed http origin result.
+	 *
+	 * @since  3.4.0
+	 * @param  string $origin Result of check for allowed origin.
+	 * @param  string $origin_arg original origin string passed into is_allowed_http_origin function.
+	 */
 	return apply_filters( 'allowed_http_origin', $origin, $origin_arg );
 }
 
@@ -458,6 +477,16 @@
 				|| ( 192 === $parts[0] && 168 === $parts[1] )
 			) {
 				// If host appears local, reject unless specifically allowed.
+				/**
+				 * Check if http request is external or not.
+				 *
+				 * Allows to change and allow external requests for the http request'
+				 *
+				 * @since  3.6.0
+				 * @param  bool false Whether http request is external or not.
+				 * @param  string $host IP of the requested host.
+				 * @param  string $url URL of the requested host.
+				 */
 				if ( ! apply_filters( 'http_request_host_is_external', false, $host, $url ) )
 					return false;
 			}