The command dnf download ignores install_weak_deps=0.

Why:

Download plugin contains code:

    def _get_packages_with_deps(self, pkg_specs, source=False):
        """Get packages matching pkg_specs and the deps."""

            ...

            rc = goal.run()


            ...

As you can see, it does not fill parameter 

ignore_weak_deps=(not conf.install_weak_deps))

as it does in dnf/base.py

It's important since it download more .src.rpm files than it should (in my case).

P.S. Actually, it is triggered in Fedora 34, but I believe the problem is still here. https://github.com/rpm-software-management/dnf-plugins-core/blob/master/plugins/download.py#L256