build_binary_package_impl copied the whole parent directory into the build root (ensure_available) and then retrieved every *.deb / *.changes / *.buildinfo it found there. That surfaced stale files already sitting next to the package tree in the "Built in Ns:" summary. Now local::build returns the exact set of artifacts produced by this build — the binary packages registered in debian/files plus the generated .buildinfo/.changes from generate_binary_metadata — and build_binary_package_impl retrieves that list instead of globbing the build root. Only files genuinely produced by the current build are printed.