Gem::Commands::ContentsCommand#spec_for

# File tmp/rubies/ruby-3.0.5/lib/rubygems/commands/contents_command.rb, line 168
def spec_for(name)
  spec = Gem::Specification.find_all_by_name(name, @version).first

  return spec if spec

  say "Unable to find gem '#{name}' in #{@path_kind}"

  if Gem.configuration.verbose
    say "\nDirectories searched:"
    @spec_dirs.sort.each {|dir| say dir }
  end

  return nil
end