/usr/lib/ruby/vendor_ruby/ is in ruby-rgfa 1.3.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/rgfa/
/usr/lib/ruby/vendor_ruby/rgfa/byte_array.rb
/usr/lib/ruby/vendor_ruby/rgfa/cigar.rb
/usr/lib/ruby/vendor_ruby/rgfa/connectivity.rb
/usr/lib/ruby/vendor_ruby/rgfa/containments.rb
/usr/lib/ruby/vendor_ruby/rgfa/error.rb
/usr/lib/ruby/vendor_ruby/rgfa/field_array.rb
/usr/lib/ruby/vendor_ruby/rgfa/field_parser.rb
/usr/lib/ruby/vendor_ruby/rgfa/field_validator.rb
/usr/lib/ruby/vendor_ruby/rgfa/field_writer.rb
/usr/lib/ruby/vendor_ruby/rgfa/headers.rb
/usr/lib/ruby/vendor_ruby/rgfa/line/
/usr/lib/ruby/vendor_ruby/rgfa/line/comment.rb
/usr/lib/ruby/vendor_ruby/rgfa/line/containment.rb
/usr/lib/ruby/vendor_ruby/rgfa/line/header.rb
/usr/lib/ruby/vendor_ruby/rgfa/line/link.rb
/usr/lib/ruby/vendor_ruby/rgfa/line/path.rb
/usr/lib/ruby/vendor_ruby/rgfa/line/segment.rb
/usr/lib/ruby/vendor_ruby/rgfa/line.rb
/usr/lib/ruby/vendor_ruby/rgfa/linear_paths.rb
/usr/lib/ruby/vendor_ruby/rgfa/lines.rb
/usr/lib/ruby/vendor_ruby/rgfa/links.rb
/usr/lib/ruby/vendor_ruby/rgfa/logger.rb
/usr/lib/ruby/vendor_ruby/rgfa/multiplication.rb
/usr/lib/ruby/vendor_ruby/rgfa/numeric_array.rb
/usr/lib/ruby/vendor_ruby/rgfa/paths.rb
/usr/lib/ruby/vendor_ruby/rgfa/rgl.rb
/usr/lib/ruby/vendor_ruby/rgfa/segment_ends_path.rb
/usr/lib/ruby/vendor_ruby/rgfa/segment_info.rb
/usr/lib/ruby/vendor_ruby/rgfa/segments.rb
/usr/lib/ruby/vendor_ruby/rgfa/sequence.rb
/usr/lib/ruby/vendor_ruby/rgfa.rb
/usr/lib/ruby/vendor_ruby/rgfatools/
/usr/lib/ruby/vendor_ruby/rgfatools/artifacts.rb
/usr/lib/ruby/vendor_ruby/rgfatools/copy_number.rb
/usr/lib/ruby/vendor_ruby/rgfatools/invertible_segments.rb
/usr/lib/ruby/vendor_ruby/rgfatools/linear_paths.rb
/usr/lib/ruby/vendor_ruby/rgfatools/multiplication.rb
/usr/lib/ruby/vendor_ruby/rgfatools/p_bubbles.rb
/usr/lib/ruby/vendor_ruby/rgfatools/superfluous_links.rb
/usr/lib/ruby/vendor_ruby/rgfatools.rb