/usr/share/php/Icinga/Web/Widget/ is in php-icinga 2.1.0-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/php/Icinga/Web/Widget/AbstractWidget.php
/usr/share/php/Icinga/Web/Widget/Chart/
/usr/share/php/Icinga/Web/Widget/Chart/HistoryColorGrid.php
/usr/share/php/Icinga/Web/Widget/Chart/InlinePie.php
/usr/share/php/Icinga/Web/Widget/Dashboard/
/usr/share/php/Icinga/Web/Widget/Dashboard.php
/usr/share/php/Icinga/Web/Widget/Dashboard/Dashlet.php
/usr/share/php/Icinga/Web/Widget/Dashboard/Pane.php
/usr/share/php/Icinga/Web/Widget/Dashboard/UserWidget.php
/usr/share/php/Icinga/Web/Widget/FilterEditor.php
/usr/share/php/Icinga/Web/Widget/FilterWidget.php
/usr/share/php/Icinga/Web/Widget/Limiter.php
/usr/share/php/Icinga/Web/Widget/Paginator.php
/usr/share/php/Icinga/Web/Widget/SearchDashboard.php
/usr/share/php/Icinga/Web/Widget/SortBox.php
/usr/share/php/Icinga/Web/Widget/Tab.php
/usr/share/php/Icinga/Web/Widget/Tabextension/
/usr/share/php/Icinga/Web/Widget/Tabextension/DashboardAction.php
/usr/share/php/Icinga/Web/Widget/Tabextension/DashboardSettings.php
/usr/share/php/Icinga/Web/Widget/Tabextension/MenuAction.php
/usr/share/php/Icinga/Web/Widget/Tabextension/OutputFormat.php
/usr/share/php/Icinga/Web/Widget/Tabextension/Tabextension.php
/usr/share/php/Icinga/Web/Widget/Tabs.php
/usr/share/php/Icinga/Web/Widget/Widget.php