/usr/lib/ruby/vendor_ruby/rspec/mocks/standalone.rb is in ruby-rspec-mocks 3.5.0c3e0m0s0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | require 'rspec/mocks'
extend RSpec::Mocks::ExampleMethods
RSpec::Mocks.setup
|