https://pagure.io/fedora-infrastructure/issue/12169

Now I finally realized that the mirror manager responds on different URLs for
s390x and for the other architectures:

```diff

• https://mirrors.centos.org/metalink?repo=centos-extras-sig-extra-common-10-stream&arch=s390x&protocol=https,http
  + https://mirrors.centos.org/metalink?repo=centos-extras-sig-extras-common-10-stream&arch=x86_64&protocol=https,http
  ```
  Note the difference in `s/extra/extras`. This should be synchronized, or just
  please conifrm this is the status quo is expected.

We try to fix the default Mock configuration [for s390x problem](https://github.com/rpm-software-management/mock/pull/1388), also reported [to CS](https://issues.redhat.com/browse/CS-2288).