/usr/lib/ruby/vendor_ruby/bundler/templates/newgem/Gemfile.tt is in ruby-bundler 1.13.6-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | source 'https://rubygems.org'
# Specify your gem's dependencies in <%=config[:name]%>.gemspec
gemspec
|