/usr/ is in ruby-method-source 0.9.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/ruby/
/usr/lib/ruby/vendor_ruby/
/usr/lib/ruby/vendor_ruby/method_source/
/usr/lib/ruby/vendor_ruby/method_source/code_helpers.rb
/usr/lib/ruby/vendor_ruby/method_source/source_location.rb
/usr/lib/ruby/vendor_ruby/method_source/version.rb
/usr/lib/ruby/vendor_ruby/method_source.rb
/usr/share/
/usr/share/doc/
/usr/share/doc/ruby-method-source/
/usr/share/doc/ruby-method-source/README.markdown
/usr/share/doc/ruby-method-source/changelog.Debian.gz
/usr/share/doc/ruby-method-source/copyright
/usr/share/rubygems-integration/
/usr/share/rubygems-integration/all/
/usr/share/rubygems-integration/all/specifications/
/usr/share/rubygems-integration/all/specifications/method_source-0.9.0.gemspec