/usr/share/php/Sabre/DAV/Exception/ is in php-sabre-dav 1.8.12-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Sabre/DAV/Exception/BadRequest.php
/usr/share/php/Sabre/DAV/Exception/Conflict.php
/usr/share/php/Sabre/DAV/Exception/ConflictingLock.php
/usr/share/php/Sabre/DAV/Exception/FileNotFound.php
/usr/share/php/Sabre/DAV/Exception/Forbidden.php
/usr/share/php/Sabre/DAV/Exception/InsufficientStorage.php
/usr/share/php/Sabre/DAV/Exception/InvalidResourceType.php
/usr/share/php/Sabre/DAV/Exception/LengthRequired.php
/usr/share/php/Sabre/DAV/Exception/LockTokenMatchesRequestUri.php
/usr/share/php/Sabre/DAV/Exception/Locked.php
/usr/share/php/Sabre/DAV/Exception/MethodNotAllowed.php
/usr/share/php/Sabre/DAV/Exception/NotAuthenticated.php
/usr/share/php/Sabre/DAV/Exception/NotFound.php
/usr/share/php/Sabre/DAV/Exception/NotImplemented.php
/usr/share/php/Sabre/DAV/Exception/PaymentRequired.php
/usr/share/php/Sabre/DAV/Exception/PreconditionFailed.php
/usr/share/php/Sabre/DAV/Exception/ReportNotSupported.php
/usr/share/php/Sabre/DAV/Exception/RequestedRangeNotSatisfiable.php
/usr/share/php/Sabre/DAV/Exception/ServiceUnavailable.php
/usr/share/php/Sabre/DAV/Exception/UnsupportedMediaType.php