/usr/include/kdevplatform/language/codecompletion/ is in kdevelop-dev 4:5.2.1-1ubuntu4.
This file is owned by root:root, with mode 0o755.
..
/usr/include/kdevplatform/language/codecompletion/abstractincludefilecompletionitem.h
/usr/include/kdevplatform/language/codecompletion/codecompletion.h
/usr/include/kdevplatform/language/codecompletion/codecompletioncontext.h
/usr/include/kdevplatform/language/codecompletion/codecompletionhelper.h
/usr/include/kdevplatform/language/codecompletion/codecompletionitem.h
/usr/include/kdevplatform/language/codecompletion/codecompletionitemgrouper.h
/usr/include/kdevplatform/language/codecompletion/codecompletionmodel.h
/usr/include/kdevplatform/language/codecompletion/codecompletiontesthelper.h
/usr/include/kdevplatform/language/codecompletion/codecompletionworker.h
/usr/include/kdevplatform/language/codecompletion/normaldeclarationcompletionitem.h