Why two dots in myrobot.urdf.xacro filename

Below code is from URDF course

<param name="robot_description"
  command="$(find xacro)/xacro '$(find my_robot_description)/robots/myrobot.urdf.xacro'" />

Here we have the extension myrobot.urdf.xacro', i see that there are two dots here, one between myrobot and urdf and the other between urdf and xacro. The dot between urdf and xacro seems straightforward. I want to know if the dot between myrobot and urdf has any significance or is it treated as part of the filename?

It is treated as part of the file name.