/usr/share/common-lisp/ros/diagnostic_msgs/ is in cl-diagnostic-msgs 1.12.3-5.
This file is owned by root:root, with mode 0o755.
..
/usr/share/common-lisp/ros/diagnostic_msgs/msg/
/usr/share/common-lisp/ros/diagnostic_msgs/msg/DiagnosticArray.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/msg/DiagnosticStatus.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/msg/KeyValue.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/msg/_package.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/msg/_package_DiagnosticArray.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/msg/_package_DiagnosticStatus.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/msg/_package_KeyValue.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/msg/diagnostic_msgs-msg.asd
/usr/share/common-lisp/ros/diagnostic_msgs/srv/
/usr/share/common-lisp/ros/diagnostic_msgs/srv/SelfTest.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/srv/_package.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/srv/_package_SelfTest.lisp
/usr/share/common-lisp/ros/diagnostic_msgs/srv/diagnostic_msgs-srv.asd