There was already a non packager scitech-sig group and it was not trivial to change it to a packager group, which is why we had to settle for a new scitech_sig FAS group for packages.
More information here: https://pagure.io/fedora-infrastructure/issue/8413
In my understanding, what I mentioned for https://koschei.fedoraproject.org/groups is not FAS group. The group I mentioned is just to group the RPM packages.
https://koschei.fedoraproject.org/groups/ruby-rails For example there is a "ruby-rails" group.
https://developer.fedoraproject.org/tech/languages/ruby/ror-installation.htm...
$ sudo dnf group install 'Ruby on Rails'
It is used for the group install. "ruby-rails" group has the name attribute 'Ruby on Rails'.