The tutorial (http://wiki.ros.org/rviz/Tutorials/Markers%3A%20Basic%20Shapes) needs to update the following line -

  47     marker.header.frame_id = "/my_frame";

I think tf2 does not accept the '/' in the front of a frame name. I got the following error which indicates this -

invalid argument passed to cantransform argument source_frame in tf2 frame_ids cannot start with a '/' like:

Any directions on how to submit a PR would be appreciated. Thanks!

I'm using ROS Noetic.