/usr/include/libcmis-0.5/libcmis/ is in libcmis-dev 0.5.1-2ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libcmis-0.5/libcmis/allowable-actions.hxx
/usr/include/libcmis-0.5/libcmis/document.hxx
/usr/include/libcmis-0.5/libcmis/exception.hxx
/usr/include/libcmis-0.5/libcmis/folder.hxx
/usr/include/libcmis-0.5/libcmis/libcmis.hxx
/usr/include/libcmis-0.5/libcmis/oauth2-data.hxx
/usr/include/libcmis-0.5/libcmis/object-type.hxx
/usr/include/libcmis-0.5/libcmis/object.hxx
/usr/include/libcmis-0.5/libcmis/property-type.hxx
/usr/include/libcmis-0.5/libcmis/property.hxx
/usr/include/libcmis-0.5/libcmis/rendition.hxx
/usr/include/libcmis-0.5/libcmis/repository.hxx
/usr/include/libcmis-0.5/libcmis/session-factory.hxx
/usr/include/libcmis-0.5/libcmis/session.hxx
/usr/include/libcmis-0.5/libcmis/xml-utils.hxx
/usr/include/libcmis-0.5/libcmis/xmlserializable.hxx