/usr/ is in libqtassistantclient-dev 4.6.3-7.
This file is owned by root:root, with mode 0o755.
..
/usr/share/
/usr/share/qt4/
/usr/share/qt4/mkspecs/
/usr/share/qt4/mkspecs/features/
/usr/share/qt4/mkspecs/features/assistant.prf
/usr/share/doc/
/usr/share/doc/libqtassistantclient-dev/
/usr/share/doc/libqtassistantclient-dev/copyright
/usr/lib/
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/libQtAssistantClient.prl
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/QtAssistantClient.pc
/usr/include/
/usr/include/qt4/
/usr/include/qt4/QtAssistant/
/usr/include/qt4/QtAssistant/QtAssistant
/usr/include/qt4/QtAssistant/qassistantclient.h
/usr/include/qt4/QtAssistant/qassistantclient_global.h
/usr/include/qt4/QtAssistant/QAssistantClient
/usr/share/doc/libqtassistantclient-dev/changelog.Debian.gz
/usr/lib/x86_64-linux-gnu/libQtAssistantClient.so