Dubious detection as META.yml "license=open_source" as "SUSE-Public-domain"

[okurz]

I found this change following https://build.opensuse.org/requests/1281390/actions/3538754#tab-pane-changes . I don't understand why license=open_source should be understood as "SUSE-PublicDomain". "unrestricted" sounds equivalent to "PublicDomain" but just "open_source" without further license details needs to be treated much more restrictive.

Originally posted by @okurz in b4f70a7