/usr/lib/ruby/vendor_ruby/ is in ruby-gobject-introspection 2.1.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/gobject-introspection.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/
/usr/lib/ruby/vendor_ruby/gobject-introspection/object-info.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/interface-info.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/struct-info.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/repository.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/boxed-info.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/callable-info.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/union-info.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/collection-reader.rb
/usr/lib/ruby/vendor_ruby/gobject-introspection/loader.rb
/usr/lib/ruby/vendor_ruby/1.9.1/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/
/usr/lib/ruby/vendor_ruby/1.9.1/x86_64-linux/gobject_introspection.so