/usr/share/php/HTTP/Request2/ is in php-http-request2 2.3.0-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/HTTP/Request2/Adapter/
/usr/share/php/HTTP/Request2/Adapter.php
/usr/share/php/HTTP/Request2/Adapter/Curl.php
/usr/share/php/HTTP/Request2/Adapter/Mock.php
/usr/share/php/HTTP/Request2/Adapter/Socket.php
/usr/share/php/HTTP/Request2/CookieJar.php
/usr/share/php/HTTP/Request2/Exception.php
/usr/share/php/HTTP/Request2/MultipartBody.php
/usr/share/php/HTTP/Request2/Observer/
/usr/share/php/HTTP/Request2/Observer/Log.php
/usr/share/php/HTTP/Request2/Observer/UncompressingDownload.php
/usr/share/php/HTTP/Request2/Response.php
/usr/share/php/HTTP/Request2/SOCKS5.php
/usr/share/php/HTTP/Request2/SocketWrapper.php