diff --git a/src/MessageInterface.php b/src/MessageInterface.php
index dd46e5e..1f48075 100644
--- a/src/MessageInterface.php
+++ b/src/MessageInterface.php
@@ -1,4 +1,15 @@
 <?php
+/**
+ * PHP Framework Interop Group
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) PHP Framework Interop Group (https://www.php-fig.org)
+ * @link          https://www.php-fig.org/psr/psr-7/
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
 
 namespace Psr\Http\Message;
 
diff --git a/src/RequestInterface.php b/src/RequestInterface.php
index a96d4fd..fb610ff 100644
--- a/src/RequestInterface.php
+++ b/src/RequestInterface.php
@@ -1,4 +1,15 @@
 <?php
+/**
+ * PHP Framework Interop Group
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) PHP Framework Interop Group (https://www.php-fig.org)
+ * @link          https://www.php-fig.org/psr/psr-7/
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
 
 namespace Psr\Http\Message;
 
@@ -55,7 +66,7 @@ public function getRequestTarget();
      *
      * @link http://tools.ietf.org/html/rfc7230#section-5.3 (for the various
      *     request-target forms allowed in request messages)
-     * @param mixed $requestTarget
+     * @param mixed $requestTarget The request target.
      * @return static
      */
     public function withRequestTarget($requestTarget);
diff --git a/src/ResponseInterface.php b/src/ResponseInterface.php
index c306514..f563466 100644
--- a/src/ResponseInterface.php
+++ b/src/ResponseInterface.php
@@ -1,4 +1,15 @@
 <?php
+/**
+ * PHP Framework Interop Group
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) PHP Framework Interop Group (https://www.php-fig.org)
+ * @link          https://www.php-fig.org/psr/psr-7/
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
 
 namespace Psr\Http\Message;
 
diff --git a/src/ServerRequestInterface.php b/src/ServerRequestInterface.php
index 0251234..27deb73 100644
--- a/src/ServerRequestInterface.php
+++ b/src/ServerRequestInterface.php
@@ -1,4 +1,15 @@
 <?php
+/**
+ * PHP Framework Interop Group
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) PHP Framework Interop Group (https://www.php-fig.org)
+ * @link          https://www.php-fig.org/psr/psr-7/
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
 
 namespace Psr\Http\Message;
 
diff --git a/src/StreamInterface.php b/src/StreamInterface.php
index f68f391..896eb15 100644
--- a/src/StreamInterface.php
+++ b/src/StreamInterface.php
@@ -1,4 +1,15 @@
 <?php
+/**
+ * PHP Framework Interop Group
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) PHP Framework Interop Group (https://www.php-fig.org)
+ * @link          https://www.php-fig.org/psr/psr-7/
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
 
 namespace Psr\Http\Message;
 
@@ -82,6 +93,7 @@ public function isSeekable();
      *     PHP $whence values for `fseek()`.  SEEK_SET: Set position equal to
      *     offset bytes SEEK_CUR: Set position to current location plus offset
      *     SEEK_END: Set position to end-of-stream plus offset.
+     * @return int
      * @throws \RuntimeException on failure.
      */
     public function seek($offset, $whence = SEEK_SET);
@@ -94,6 +106,7 @@ public function seek($offset, $whence = SEEK_SET);
      *
      * @see seek()
      * @link http://www.php.net/manual/en/function.fseek.php
+     * @return int
      * @throws \RuntimeException on failure.
      */
     public function rewind();
diff --git a/src/UploadedFileInterface.php b/src/UploadedFileInterface.php
index f8a6901..deeb2b6 100644
--- a/src/UploadedFileInterface.php
+++ b/src/UploadedFileInterface.php
@@ -1,4 +1,15 @@
 <?php
+/**
+ * PHP Framework Interop Group
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) PHP Framework Interop Group (https://www.php-fig.org)
+ * @link          https://www.php-fig.org/psr/psr-7/
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
 
 namespace Psr\Http\Message;
 
@@ -58,12 +69,13 @@ public function getStream();
      * @see http://php.net/is_uploaded_file
      * @see http://php.net/move_uploaded_file
      * @param string $targetPath Path to which to move the uploaded file.
+     * @return bool
      * @throws \InvalidArgumentException if the $targetPath specified is invalid.
      * @throws \RuntimeException on any error during the move operation, or on
      *     the second or subsequent call to the method.
      */
     public function moveTo($targetPath);
-    
+
     /**
      * Retrieve the file size.
      *
@@ -74,7 +86,7 @@ public function moveTo($targetPath);
      * @return int|null The file size in bytes or null if unknown.
      */
     public function getSize();
-    
+
     /**
      * Retrieve the error associated with the uploaded file.
      *
@@ -90,7 +102,7 @@ public function getSize();
      * @return int One of PHP's UPLOAD_ERR_XXX constants.
      */
     public function getError();
-    
+
     /**
      * Retrieve the filename sent by the client.
      *
@@ -105,7 +117,7 @@ public function getError();
      *     was provided.
      */
     public function getClientFilename();
-    
+
     /**
      * Retrieve the media type sent by the client.
      *
diff --git a/src/UriInterface.php b/src/UriInterface.php
index 9d7ab9e..944da15 100644
--- a/src/UriInterface.php
+++ b/src/UriInterface.php
@@ -1,4 +1,16 @@
 <?php
+/**
+ * PHP Framework Interop Group
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) PHP Framework Interop Group (https://www.php-fig.org)
+ * @link          https://www.php-fig.org/psr/psr-7/
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
+
 namespace Psr\Http\Message;
 
 /**