Package: libruby2.3 Version: 2.3.1-1 Severity: normal There no longer is an "optional" ruby version, probably because of removal of ruby2.2. ruby2.3 is priority extra.
As a result, ruby packages can no longer be priority optional, since no alternative version is optional. (policy 2.5) Please raise the priority of ruby2.3 from extra to optionnal.