Package: mandos-client Version: 1.8.19-1.1 mandos-client.postinst uses dpkg-architecture to compute a multiarch path. The result of such a computation at runtime will likely produce a wrong result if the package is installed for a foreign architecture. It is best practice to compute and interpolate the multiarch tuple at package build time. For this purpose, dh_installdeb substituted #DEB_HOST_MULTIARCH#. While at it, I also observe that the postinst does not contain #DEBHELPER# and thereby strips any debhelper-generated maintainer snippets. Is that intentional?
Helmut

