diff --git a/core/lib/Drupal/Core/FileTransfer/ChmodInterface.php b/core/lib/Drupal/Core/FileTransfer/ChmodInterface.php
index baabbc5..d9035f7 100644
--- a/core/lib/Drupal/Core/FileTransfer/ChmodInterface.php
+++ b/core/lib/Drupal/Core/FileTransfer/ChmodInterface.php
@@ -8,7 +8,7 @@
 namespace Drupal\Core\FileTransfer;
 
 /**
- * A FileTransfer Class implementing this interface can be used to chmod files.
+ * Defines an interface to chmod files.
  */
 interface ChmodInterface {
 
@@ -17,10 +17,12 @@ interface ChmodInterface {
    *
    * @param string $path
    *   Path to change permissions of.
-   * @param long $mode
-   *   @see http://php.net/chmod
-   * @param boolean $recursive
+   * @param int $mode
+   *   See the $mode argument from http://php.net/chmod.
+   * @param bool $recursive
    *   Pass TRUE to recursively chmod the entire directory specified in $path.
+   *
+   * @see http://php.net/chmod
    */
   function chmodJailed($path, $mode, $recursive);
 }
diff --git a/core/lib/Drupal/Core/FileTransfer/FTP.php b/core/lib/Drupal/Core/FileTransfer/FTP.php
index 34998f1..342660a 100644
--- a/core/lib/Drupal/Core/FileTransfer/FTP.php
+++ b/core/lib/Drupal/Core/FileTransfer/FTP.php
@@ -8,10 +8,13 @@
 namespace Drupal\Core\FileTransfer;
 
 /**
- * Base class for FTP implementations.
+ * Defines the base class for FTP implementations.
  */
 abstract class FTP extends FileTransfer {
 
+  /**
+   * Overrides Drupal\Core\FileTransfer\FileTransfer::__construct().
+   */
   public function __construct($jail, $username, $password, $hostname, $port) {
     $this->username = $username;
     $this->password = $password;
@@ -21,14 +24,7 @@ abstract class FTP extends FileTransfer {
   }
 
   /**
-   * Return an object which can implement the FTP protocol.
-   *
-   * @param string $jail
-   * @param array $settings
-   *
-   * @return FTP
-   *   The appropriate FTP subclass based on the available
-   *   options. If the FTP PHP extension is available, use it.
+   * Overrides Drupal\Core\FileTransfer\FileTransfer::factory().
    */
   static function factory($jail, $settings) {
     $username = empty($settings['username']) ? '' : $settings['username'];
@@ -47,7 +43,7 @@ abstract class FTP extends FileTransfer {
   }
 
   /**
-   * Returns the form to configure the FileTransfer class for FTP.
+   * Overrides Drupal\Core\FileTransfer\FileTransfer::getSettingsForm().
    */
   public function getSettingsForm() {
     $form = parent::getSettingsForm();
diff --git a/core/lib/Drupal/Core/FileTransfer/FTPExtension.php b/core/lib/Drupal/Core/FileTransfer/FTPExtension.php
index e746a84..39465ba 100644
--- a/core/lib/Drupal/Core/FileTransfer/FTPExtension.php
+++ b/core/lib/Drupal/Core/FileTransfer/FTPExtension.php
@@ -7,8 +7,14 @@
 
 namespace Drupal\Core\FileTransfer;
 
+/**
+ * Defines a file transfer class using the PHP FTP extension.
+ */
 class FTPExtension extends FTP implements ChmodInterface {
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::connect().
+   */
   public function connect() {
     $this->connection = ftp_connect($this->hostname, $this->port);
 
@@ -20,18 +26,27 @@ class FTPExtension extends FTP implements ChmodInterface {
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::copyFileJailed().
+   */
   protected function copyFileJailed($source, $destination) {
     if (!@ftp_put($this->connection,  $destination, $source, FTP_BINARY)) {
       throw new FileTransferException("Cannot move @source to @destination", NULL, array("@source" => $source, "@destination" => $destination));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::createDirectoryJailed().
+   */
   protected function createDirectoryJailed($directory) {
     if (!ftp_mkdir($this->connection, $directory)) {
       throw new FileTransferException("Cannot create directory @directory", NULL, array("@directory" => $directory));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::removeDirectoryJailed().
+   */
   protected function removeDirectoryJailed($directory) {
     $pwd = ftp_pwd($this->connection);
     if (!ftp_chdir($this->connection, $directory)) {
@@ -59,12 +74,18 @@ class FTPExtension extends FTP implements ChmodInterface {
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::removeFileJailed().
+   */
   protected function removeFileJailed($destination) {
     if (!ftp_delete($this->connection, $destination)) {
       throw new FileTransferException("Unable to remove to file @file", NULL, array('@file' => $destination));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::isDirectory().
+   */
   public function isDirectory($path) {
     $result = FALSE;
     $curr = ftp_pwd($this->connection);
@@ -75,10 +96,16 @@ class FTPExtension extends FTP implements ChmodInterface {
     return $result;
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::isFile().
+   */
   public function isFile($path) {
     return ftp_size($this->connection, $path) != -1;
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\ChmodInterface::chmodJailed().
+   */
   function chmodJailed($path, $mode, $recursive) {
     if (!ftp_chmod($this->connection, $mode, $path)) {
       throw new FileTransferException("Unable to set permissions on %file", NULL, array ('%file' => $path));
diff --git a/core/lib/Drupal/Core/FileTransfer/FileTransfer.php b/core/lib/Drupal/Core/FileTransfer/FileTransfer.php
index 54417d0..46ba9b0 100644
--- a/core/lib/Drupal/Core/FileTransfer/FileTransfer.php
+++ b/core/lib/Drupal/Core/FileTransfer/FileTransfer.php
@@ -20,21 +20,55 @@ use RecursiveDirectoryIterator;
  * safety, all methods operate only inside a "jail", by default the Drupal root.
  */
 abstract class FileTransfer {
+
+  /**
+   * The username for this file transfer.
+   *
+   * @var string
+   */
   protected $username;
+
+  /**
+   * The password for this file transfer.
+   *
+   * @var string
+   */
   protected $password;
+
+  /**
+   * The hostname for this file transfer.
+   *
+   * @var string
+   */
   protected $hostname = 'localhost';
+
+  /**
+   * The port for this file transfer.
+   *
+   * @var int
+   */
   protected $port;
 
   /**
-   * The constructor for the UpdateConnection class. This method is also called
-   * from the classes that extend this class and override this method.
+   * Constructs a Drupal\Core\FileTransfer\FileTransfer object.
+   *
+   * This method is also called from the classes that extend this class and
+   * override this method.
+   *
+   * @param $jail
+   *   The full path where all file operations performed by this object will
+   *   be restricted to. This prevents the FileTransfer classes from being
+   *   able to touch other parts of the filesystem.
    */
   function __construct($jail) {
     $this->jail = $jail;
   }
 
   /**
+   * Defines a factory method for this class.
+   *
    * Classes that extend this class must override the factory() static method.
+   * They should return a new instance of the appropriate FileTransfer subclass.
    *
    * @param string $jail
    *   The full path where all file operations performed by this object will
@@ -44,19 +78,28 @@ abstract class FileTransfer {
    *   An array of connection settings for the FileTransfer subclass. If the
    *   getSettingsForm() method uses any nested settings, the same structure
    *   will be assumed here.
+   *
    * @return object
    *   New instance of the appropriate FileTransfer subclass.
+   *
+   * @throws Drupal\Core\FileTransfer\FileTransferException
    */
   static function factory($jail, $settings) {
     throw new FileTransferException('FileTransfer::factory() static method not overridden by FileTransfer subclass.');
   }
 
   /**
-   * Implementation of the magic __get() method.
+   * Implements the magic __get() method.
+   *
+   * If the connection isn't set to anything, this will call the connect()
+   * method and return the result; afterwards, the connection will be returned
+   * directly without using this method.
    *
-   * If the connection isn't set to anything, this will call the connect() method
-   * and set it to and return the result; afterwards, the connection will be
-   * returned directly without using this method.
+   * @param string $name
+   *   The name of the variable to return.
+   *
+   * @return string|bool
+   *   The variable specified in $name.
    */
   function __get($name) {
     if ($name == 'connection') {
@@ -78,9 +121,9 @@ abstract class FileTransfer {
   /**
    * Copies a directory.
    *
-   * @param $source
+   * @param string $source
    *   The source path.
-   * @param $destination
+   * @param string $destination
    *   The destination path.
    */
   public final function copyDirectory($source, $destination) {
@@ -91,11 +134,18 @@ abstract class FileTransfer {
   }
 
   /**
-   * @see http://php.net/chmod
+   * Changes the permissions of the specified $path (file or directory).
    *
    * @param string $path
-   * @param long $mode
+   *   The file / directory to change the permissions of.
+   * @param int $mode
+   *   See the $mode argument from http://php.net/chmod.
    * @param bool $recursive
+   *   Pass TRUE to recursively chmod the entire directory specified in $path.
+   *
+   * @throws Drupal\Core\FileTransfer\FileTransferException
+   *
+   * @see http://php.net/chmod
    */
   public final function chmod($path, $mode, $recursive = FALSE) {
     if (!in_array('Drupal\Core\FileTransfer\ChmodInterface', class_implements(get_class($this)))) {
@@ -110,7 +160,7 @@ abstract class FileTransfer {
   /**
    * Creates a directory.
    *
-   * @param $directory
+   * @param string $directory
    *   The directory to be created.
    */
   public final function createDirectory($directory) {
@@ -122,7 +172,7 @@ abstract class FileTransfer {
   /**
    * Removes a directory.
    *
-   * @param $directory
+   * @param string $directory
    *   The directory to be removed.
    */
   public final function removeDirectory($directory) {
@@ -134,9 +184,9 @@ abstract class FileTransfer {
   /**
    * Copies a file.
    *
-   * @param $source
+   * @param string $source
    *   The source file.
-   * @param $destination
+   * @param string $destination
    *   The destination file.
    */
   public final function copyFile($source, $destination) {
@@ -149,7 +199,7 @@ abstract class FileTransfer {
   /**
    * Removes a file.
    *
-   * @param $destination
+   * @param string $destination
    *   The destination file to be removed.
    */
   public final function removeFile($destination) {
@@ -161,8 +211,10 @@ abstract class FileTransfer {
   /**
    * Checks that the path is inside the jail and throws an exception if not.
    *
-   * @param $path
+   * @param string $path
    *   A path to check against the jail.
+   *
+   * @throws Drupal\Core\FileTransfer\FileTransferException
    */
   protected final function checkPath($path) {
     $full_jail = $this->chroot . $this->jail;
@@ -175,14 +227,18 @@ abstract class FileTransfer {
 
   /**
    * Returns a modified path suitable for passing to the server.
-   * If a path is a windows path, makes it POSIX compliant by removing the drive letter.
-   * If $this->chroot has a value, it is stripped from the path to allow for
-   * chroot'd filetransfer systems.
    *
-   * @param $path
-   * @param $strip_chroot
+   * If a path is a windows path, makes it POSIX compliant by removing the drive
+   * letter. If $this->chroot has a value, it is stripped from the path to allow
+   * for chroot'd filetransfer systems.
+   *
+   * @param string $path
+   *   The path to modify.
+   * @param bool $strip_chroot
+   *   Whether to remove the path in $this->chroot.
    *
    * @return string
+   *   The modified path.
    */
   protected final function fixRemotePath($path, $strip_chroot = TRUE) {
     $path = $this->sanitizePath($path);
@@ -199,7 +255,10 @@ abstract class FileTransfer {
   * Changes backslashes to slashes, also removes a trailing slash.
   *
   * @param string $path
+  *   The path to modify.
+  *
   * @return string
+  *   The modified path.
   */
   function sanitizePath($path) {
     $path = str_replace('\\', '/', $path); // Windows path sanitization.
@@ -212,11 +271,11 @@ abstract class FileTransfer {
   /**
    * Copies a directory.
    *
-   * We need a separate method to make the $destination is in the jail.
+   * We need a separate method to make sure the $destination is in the jail.
    *
-   * @param $source
+   * @param string $source
    *   The source path.
-   * @param $destination
+   * @param string $destination
    *   The destination path.
    */
   protected function copyDirectoryJailed($source, $destination) {
@@ -238,7 +297,7 @@ abstract class FileTransfer {
   /**
    * Creates a directory.
    *
-   * @param $directory
+   * @param string $directory
    *   The directory to be created.
    */
   abstract protected function createDirectoryJailed($directory);
@@ -246,7 +305,7 @@ abstract class FileTransfer {
   /**
    * Removes a directory.
    *
-   * @param $directory
+   * @param string $directory
    *   The directory to be removed.
    */
   abstract protected function removeDirectoryJailed($directory);
@@ -254,9 +313,9 @@ abstract class FileTransfer {
   /**
    * Copies a file.
    *
-   * @param $source
+   * @param string $source
    *   The source file.
-   * @param $destination
+   * @param string $destination
    *   The destination file.
    */
   abstract protected function copyFileJailed($source, $destination);
@@ -264,39 +323,40 @@ abstract class FileTransfer {
   /**
    * Removes a file.
    *
-   * @param $destination
+   * @param string $destination
    *   The destination file to be removed.
    */
   abstract protected function removeFileJailed($destination);
 
   /**
-   * Checks if a particular path is a directory
+   * Checks if a particular path is a directory.
    *
-   * @param $path
+   * @param string $path
    *   The path to check
    *
-   * @return boolean
+   * @return bool
+   *   TRUE if the specified path is a directory, FALSE otherwise.
    */
   abstract public function isDirectory($path);
 
   /**
    * Checks if a particular path is a file (not a directory).
    *
-   * @param $path
-   *   The path to check
+   * @param string $path
+   *   The path to check.
    *
-   * @return boolean
+   * @return bool
+   *   TRUE if the specified path is a file, FALSE otherwise.
    */
   abstract public function isFile($path);
 
   /**
    * Returns the chroot property for this connection.
    *
-   * It does this by moving up the tree until it finds itself. If successful,
-   * it will return the chroot, otherwise FALSE.
+   * It does this by moving up the tree until it finds itself
    *
-   * @return
-   *   The chroot path for this connection or FALSE.
+   * @return string|bool
+   *   If successful, the chroot path for this connection, otherwise FALSE.
    */
   function findChroot() {
     // If the file exists as is, there is no chroot.
@@ -322,8 +382,7 @@ abstract class FileTransfer {
   }
 
   /**
-   * Sets the chroot and changes the jail to match the correct path scheme
-   *
+   * Sets the chroot and changes the jail to match the correct path scheme.
    */
   function setChroot() {
     $this->chroot = $this->findChroot();
@@ -335,6 +394,9 @@ abstract class FileTransfer {
    *
    * Implementing classes can either extend this form with fields collecting the
    * specific information they need, or override it entirely.
+   *
+   * @return array
+   *   An array that contains a Form API definition.
    */
   public function getSettingsForm() {
     $form['username'] = array(
diff --git a/core/lib/Drupal/Core/FileTransfer/FileTransferException.php b/core/lib/Drupal/Core/FileTransfer/FileTransferException.php
index 0179d91..bc32af8 100644
--- a/core/lib/Drupal/Core/FileTransfer/FileTransferException.php
+++ b/core/lib/Drupal/Core/FileTransfer/FileTransferException.php
@@ -13,8 +13,24 @@ use RuntimeException;
  * FileTransferException class.
  */
 class FileTransferException extends RuntimeException {
+
+  /**
+   * Arguments to be used in this exception.
+   *
+   * @var array
+   */
   public $arguments;
 
+  /**
+   * Constructs a FileTransferException object.
+   *
+   * @param string $message
+   *   Exception message.
+   * @param int $code
+   *   Exception code.
+   * @param array $arguments
+   *   Arguments to be used in this exception.
+   */
   function __construct($message, $code = 0, $arguments = array()) {
     parent::__construct($message, $code);
     $this->arguments = $arguments;
diff --git a/core/lib/Drupal/Core/FileTransfer/Local.php b/core/lib/Drupal/Core/FileTransfer/Local.php
index 6d534ed..92ddcd9 100644
--- a/core/lib/Drupal/Core/FileTransfer/Local.php
+++ b/core/lib/Drupal/Core/FileTransfer/Local.php
@@ -11,30 +11,45 @@ use RecursiveIteratorIterator;
 use RecursiveDirectoryIterator;
 
 /**
- * The local connection class for copying files as the httpd user.
+ * Defines the local connection class for copying files as the httpd user.
  */
 class Local extends FileTransfer implements ChmodInterface {
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::connect().
+   */
   function connect() {
     // No-op
   }
 
+  /**
+   * Overrides Drupal\Core\FileTransfer\FileTransfer::factory().
+   */
   static function factory($jail, $settings) {
     return new Local($jail);
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::copyFileJailed().
+   */
   protected function copyFileJailed($source, $destination) {
     if (@!copy($source, $destination)) {
       throw new FileTransferException('Cannot copy %source to %destination.', NULL, array('%source' => $source, '%destination' => $destination));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::createDirectoryJailed().
+   */
   protected function createDirectoryJailed($directory) {
     if (!is_dir($directory) && @!mkdir($directory, 0777, TRUE)) {
       throw new FileTransferException('Cannot create directory %directory.', NULL, array('%directory' => $directory));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::removeDirectoryJailed().
+   */
   protected function removeDirectoryJailed($directory) {
     if (!is_dir($directory)) {
       // Programmer error assertion, not something we expect users to see.
@@ -57,20 +72,32 @@ class Local extends FileTransfer implements ChmodInterface {
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::removeFileJailed().
+   */
   protected function removeFileJailed($file) {
     if (@!drupal_unlink($file)) {
       throw new FileTransferException('Cannot remove file %file.', NULL, array('%file' => $file));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::isDirectory().
+   */
   public function isDirectory($path) {
     return is_dir($path);
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::isFile().
+   */
   public function isFile($path) {
     return is_file($path);
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\ChmodInterface::chmodJailed().
+   */
   public function chmodJailed($path, $mode, $recursive) {
     if ($recursive && is_dir($path)) {
       foreach (new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path, RecursiveDirectoryIterator::SKIP_DOTS), RecursiveIteratorIterator::SELF_FIRST) as $filename => $file) {
diff --git a/core/lib/Drupal/Core/FileTransfer/SSH.php b/core/lib/Drupal/Core/FileTransfer/SSH.php
index 19f68c4..c1bf991 100644
--- a/core/lib/Drupal/Core/FileTransfer/SSH.php
+++ b/core/lib/Drupal/Core/FileTransfer/SSH.php
@@ -12,6 +12,9 @@ namespace Drupal\Core\FileTransfer;
  */
 class SSH extends FileTransfer implements ChmodInterface {
 
+  /**
+   * Overrides Drupal\Core\FileTransfer\FileTransfer::__construct().
+   */
   function __construct($jail, $username, $password, $hostname = "localhost", $port = 22) {
     $this->username = $username;
     $this->password = $password;
@@ -20,6 +23,9 @@ class SSH extends FileTransfer implements ChmodInterface {
     parent::__construct($jail);
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::connect().
+   */
   function connect() {
     $this->connection = @ssh2_connect($this->hostname, $this->port);
     if (!$this->connection) {
@@ -30,6 +36,9 @@ class SSH extends FileTransfer implements ChmodInterface {
     }
   }
 
+  /**
+   * Overrides Drupal\Core\FileTransfer\FileTransfer::factory().
+   */
   static function factory($jail, $settings) {
     $username = empty($settings['username']) ? '' : $settings['username'];
     $password = empty($settings['password']) ? '' : $settings['password'];
@@ -38,30 +47,45 @@ class SSH extends FileTransfer implements ChmodInterface {
     return new SSH($jail, $username, $password, $hostname, $port);
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::copyFileJailed().
+   */
   protected function copyFileJailed($source, $destination) {
     if (!@ssh2_scp_send($this->connection, $source, $destination)) {
       throw new FileTransferException('Cannot copy @source_file to @destination_file.', NULL, array('@source' => $source, '@destination' => $destination));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::copyDirectoryJailed().
+   */
   protected function copyDirectoryJailed($source, $destination) {
     if (@!ssh2_exec($this->connection, 'cp -Rp ' . escapeshellarg($source) . ' ' . escapeshellarg($destination))) {
       throw new FileTransferException('Cannot copy directory @directory.', NULL, array('@directory' => $source));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::createDirectoryJailed().
+   */
   protected function createDirectoryJailed($directory) {
     if (@!ssh2_exec($this->connection, 'mkdir ' . escapeshellarg($directory))) {
       throw new FileTransferException('Cannot create directory @directory.', NULL, array('@directory' => $directory));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::removeDirectoryJailed().
+   */
   protected function removeDirectoryJailed($directory) {
     if (@!ssh2_exec($this->connection, 'rm -Rf ' . escapeshellarg($directory))) {
       throw new FileTransferException('Cannot remove @directory.', NULL, array('@directory' => $directory));
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::removeFileJailed().
+   */
   protected function removeFileJailed($destination) {
     if (!@ssh2_exec($this->connection, 'rm ' . escapeshellarg($destination))) {
       throw new FileTransferException('Cannot remove @directory.', NULL, array('@directory' => $destination));
@@ -69,7 +93,10 @@ class SSH extends FileTransfer implements ChmodInterface {
   }
 
   /**
-   * WARNING: This is untested.  It is not currently used, but should do the trick.
+   * Implements Drupal\Core\FileTransfer\FileTransfer::isDirectory().
+   *
+   * WARNING: This is untested. It is not currently used, but should do the
+   * trick.
    */
   public function isDirectory($path) {
     $directory = escapeshellarg($path);
@@ -84,6 +111,9 @@ class SSH extends FileTransfer implements ChmodInterface {
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\FileTransfer::isFile().
+   */
   public function isFile($path) {
     $file = escapeshellarg($path);
     $cmd = "[ -f {$file} ] && echo 'yes'";
@@ -97,6 +127,9 @@ class SSH extends FileTransfer implements ChmodInterface {
     }
   }
 
+  /**
+   * Implements Drupal\Core\FileTransfer\ChmodInterface::chmodJailed().
+   */
   function chmodJailed($path, $mode, $recursive) {
     $cmd = sprintf("chmod %s%o %s", $recursive ? '-R ' : '', $mode, escapeshellarg($path));
     if (@!ssh2_exec($this->connection, $cmd)) {
@@ -105,7 +138,7 @@ class SSH extends FileTransfer implements ChmodInterface {
   }
 
   /**
-   * Returns the form to configure the FileTransfer class for SSH.
+   * Overrides Drupal\Core\FileTransfer\FileTransfer::getSettingsForm().
    */
   public function getSettingsForm() {
     $form = parent::getSettingsForm();