/usr/ is in libflatpak-dev 0.11.3-3.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/libflatpak.so
/usr/include/
/usr/include/flatpak/
/usr/include/flatpak/flatpak-bundle-ref.h
/usr/include/flatpak/flatpak-enum-types.h
/usr/include/flatpak/flatpak-error.h
/usr/include/flatpak/flatpak-installation.h
/usr/include/flatpak/flatpak-installed-ref.h
/usr/include/flatpak/flatpak-ref.h
/usr/include/flatpak/flatpak-related-ref.h
/usr/include/flatpak/flatpak-remote-ref.h
/usr/include/flatpak/flatpak-remote.h
/usr/include/flatpak/flatpak-version-macros.h
/usr/include/flatpak/flatpak.h
/usr/lib/
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/flatpak.pc
/usr/share/
/usr/share/dbus-1/
/usr/share/dbus-1/interfaces/
/usr/share/dbus-1/interfaces/org.freedesktop.Flatpak.xml
/usr/share/doc/
/usr/share/doc/libflatpak-dev/
/usr/share/doc/libflatpak-dev/copyright
/usr/share/gir-1.0/
/usr/share/gir-1.0/Flatpak-1.0.gir
/usr/share/doc/libflatpak-dev/changelog.Debian.gz