/usr/include/ is in libkdecorations2-dev 4:5.8.4-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/KF5/
/usr/include/KDecoration2/
/usr/include/KDecoration2/KDecoration2/
/usr/include/KDecoration2/KDecoration2/DecoratedClient
/usr/include/KDecoration2/KDecoration2/Decoration
/usr/include/KDecoration2/KDecoration2/DecorationButton
/usr/include/KDecoration2/KDecoration2/DecorationButtonGroup
/usr/include/KDecoration2/KDecoration2/DecorationSettings
/usr/include/KDecoration2/KDecoration2/DecorationShadow
/usr/include/KDecoration2/KDecoration2/Private/
/usr/include/KDecoration2/KDecoration2/Private/DecoratedClientPrivate
/usr/include/KDecoration2/KDecoration2/Private/DecorationBridge
/usr/include/KDecoration2/KDecoration2/Private/DecorationSettingsPrivate
/usr/include/KDecoration2/kdecoration2/
/usr/include/KDecoration2/kdecoration2/decoratedclient.h
/usr/include/KDecoration2/kdecoration2/decoration.h
/usr/include/KDecoration2/kdecoration2/decorationbutton.h
/usr/include/KDecoration2/kdecoration2/decorationbuttongroup.h
/usr/include/KDecoration2/kdecoration2/decorationdefines.h
/usr/include/KDecoration2/kdecoration2/decorationsettings.h
/usr/include/KDecoration2/kdecoration2/decorationshadow.h
/usr/include/KDecoration2/kdecoration2/kdecoration2_export.h
/usr/include/KDecoration2/kdecoration2/private/
/usr/include/KDecoration2/kdecoration2/private/decoratedclientprivate.h
/usr/include/KDecoration2/kdecoration2/private/decorationbridge.h
/usr/include/KDecoration2/kdecoration2/private/decorationsettingsprivate.h
/usr/include/KDecoration2/kdecoration2/private/kdecoration2_private_export.h
/usr/include/KF5/kdecoration2_version.h