/usr/share/monodoc/web/plugins/sidebar-plugin/dependencies/xtree/xmlextras.js is in monodoc-http 4.2-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/monodoc/web/plugins/sidebar-plugin/dependencies/xtree/../../../../../../javascript/xmlextras/xmlextras.js