dh_install, by default, only installs files explicitly listed
in debian/<package>.install. Without that file, it silently
installs nothing — the build pipeline ends with an empty .deb
of just changelog and copyright.
List:
/usr/lib/postit/* (managed assemblies)
/usr/bin/postit (wrapper script)
/usr/share/applications/postit.desktop
/usr/share/icons/hicolor/{16,32,48,64,128,256}x{...}/apps/postit.png
/usr/share/icons/hicolor/scalable/apps/postit.svg
