Here' I can answer both questions at once:
The RubyGems site has a complete listing of all published gems. Each gem is annotated with its license and other details.
On Aug 16, 2020, at 9:25 PM, Sridevi Nanduri <firstname.lastname@example.org> wrote:
Please advise a ruby gem that does not need a license and can be used to read/write/export Excel. Where can I find information about gems and license information for ruby gems. Are all ruby gems open to public?