We call this launch file from multi_simulation_launch.py if mode command line parameter is not "simple" (it is either "slam" or "map").
In theory, as we have already modified params YAML file and XACRO
file, all we need to do here is to pass namespace and proper
params_file. I tried it, and it didn't work. But if I pass modified
params file as a new parameter, it works. Therefore, we have
an odd-looking two lines:
'namespaced_params' : namespaced_params,
I am 100% sure it is "fixable", and sooner or later I will find out how to do it right. It is not some kind of a ROS2 secret, just a bug somewhere in Nav2.