/usr/lib/ruby/vendor_ruby/log4r/rdoc/ is in ruby-log4r 1.1.10-3.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/ruby/vendor_ruby/log4r/rdoc/GDC
/usr/lib/ruby/vendor_ruby/log4r/rdoc/MDC
/usr/lib/ruby/vendor_ruby/log4r/rdoc/NDC
/usr/lib/ruby/vendor_ruby/log4r/rdoc/configurator
/usr/lib/ruby/vendor_ruby/log4r/rdoc/emailoutputter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/formatter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/log4jxmlformatter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/log4r
/usr/lib/ruby/vendor_ruby/log4r/rdoc/logger
/usr/lib/ruby/vendor_ruby/log4r/rdoc/logserver
/usr/lib/ruby/vendor_ruby/log4r/rdoc/outputter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/patternformatter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/scribeoutputter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/syslogoutputter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/win32eventoutputter
/usr/lib/ruby/vendor_ruby/log4r/rdoc/yamlconfigurator