The procedure missed an important step, added below:

On Monday, 21 November 2022 15:16:52 CET Diederik de Haas wrote:
> # Clean things up and do the actual build
> $ dpkg-architecture -c fakeroot debian/rules maintainerclean
> $ dpkg-architecture -c debian/rules orig

$ dpkg-architecture -c debian/rules debian/control

> $ time dpkg-architecture -c fakeroot debian/rules binary-indep
> $ time dpkg-architecture -c fakeroot debian/rules binary-arch