/usr/include/QHttpEngine/ is in libqhttpengine-dev 0.1.0+dfsg1-1+b2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/QHttpEngine/QFilesystemHandler
/usr/include/QHttpEngine/QHttpHandler
/usr/include/QHttpEngine/QHttpParser
/usr/include/QHttpEngine/QHttpServer
/usr/include/QHttpEngine/QHttpSocket
/usr/include/QHttpEngine/QIByteArray
/usr/include/QHttpEngine/QIODeviceCopier
/usr/include/QHttpEngine/QLocalFile
/usr/include/QHttpEngine/QObjectHandler
/usr/include/QHttpEngine/qfilesystemhandler.h
/usr/include/QHttpEngine/qhttpengine.h
/usr/include/QHttpEngine/qhttphandler.h
/usr/include/QHttpEngine/qhttpparser.h
/usr/include/QHttpEngine/qhttpserver.h
/usr/include/QHttpEngine/qhttpsocket.h
/usr/include/QHttpEngine/qibytearray.h
/usr/include/QHttpEngine/qiodevicecopier.h
/usr/include/QHttpEngine/qlocalfile.h
/usr/include/QHttpEngine/qobjecthandler.h