/usr/share/php/GuzzleHttp/ is in php-guzzlehttp-ringphp 1.1.0-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/GuzzleHttp/Ring/
/usr/share/php/GuzzleHttp/Ring/Client/
/usr/share/php/GuzzleHttp/Ring/Client/ClientUtils.php
/usr/share/php/GuzzleHttp/Ring/Client/CurlFactory.php
/usr/share/php/GuzzleHttp/Ring/Client/CurlHandler.php
/usr/share/php/GuzzleHttp/Ring/Client/CurlMultiHandler.php
/usr/share/php/GuzzleHttp/Ring/Client/Middleware.php
/usr/share/php/GuzzleHttp/Ring/Client/MockHandler.php
/usr/share/php/GuzzleHttp/Ring/Client/StreamHandler.php
/usr/share/php/GuzzleHttp/Ring/Core.php
/usr/share/php/GuzzleHttp/Ring/Exception/
/usr/share/php/GuzzleHttp/Ring/Exception/CancelledException.php
/usr/share/php/GuzzleHttp/Ring/Exception/CancelledFutureAccessException.php
/usr/share/php/GuzzleHttp/Ring/Exception/ConnectException.php
/usr/share/php/GuzzleHttp/Ring/Exception/RingException.php
/usr/share/php/GuzzleHttp/Ring/Future/
/usr/share/php/GuzzleHttp/Ring/Future/BaseFutureTrait.php
/usr/share/php/GuzzleHttp/Ring/Future/CompletedFutureArray.php
/usr/share/php/GuzzleHttp/Ring/Future/CompletedFutureValue.php
/usr/share/php/GuzzleHttp/Ring/Future/FutureArray.php
/usr/share/php/GuzzleHttp/Ring/Future/FutureArrayInterface.php
/usr/share/php/GuzzleHttp/Ring/Future/FutureInterface.php
/usr/share/php/GuzzleHttp/Ring/Future/FutureValue.php
/usr/share/php/GuzzleHttp/Ring/Future/MagicFutureTrait.php
/usr/share/php/GuzzleHttp/Ring/autoload.php