/usr/share/z-push/lib/request/ is in z-push-common 2.3.8-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/z-push/lib/request/folderchange.php
/usr/share/z-push/lib/request/foldersync.php
/usr/share/z-push/lib/request/getattachment.php
/usr/share/z-push/lib/request/gethierarchy.php
/usr/share/z-push/lib/request/getitemestimate.php
/usr/share/z-push/lib/request/itemoperations.php
/usr/share/z-push/lib/request/meetingresponse.php
/usr/share/z-push/lib/request/moveitems.php
/usr/share/z-push/lib/request/notify.php
/usr/share/z-push/lib/request/ping.php
/usr/share/z-push/lib/request/provisioning.php
/usr/share/z-push/lib/request/request.php
/usr/share/z-push/lib/request/requestprocessor.php
/usr/share/z-push/lib/request/resolverecipients.php
/usr/share/z-push/lib/request/search.php
/usr/share/z-push/lib/request/sendmail.php
/usr/share/z-push/lib/request/settings.php
/usr/share/z-push/lib/request/sync.php
/usr/share/z-push/lib/request/validatecert.php