launch file

edit

hi,all can anyone explain me please ,what the following content of that launchfile (from tutorial: http://www.ros.org/wiki/simulator_gazebo/Tutorial/SpawningObjectInSimulation means???

<launch>
  <!-- send table urdf to param server -->
  <param name="table_description" command="$(find xacro)/xacro.py $(find gazebo_worlds)/objects/table.urdf.xacro" />

  <!-- push table_description to factory and spawn robot in gazebo -->
  <node name="spawn_table" pkg="gazebo" type="spawn_model" args="-urdf -param table_description -z 0.01 -model table_model" respawn="false" output="screen" />
</launch>

the interesting part for me is : <node name="spawn_table" pkg="gazebo" type="spawn_model" args="-urdf -param table_description -z 0.01 -model table_model" <="" p="">

is spawn_table a (standard) node within the gazebo stack?But i cant find that node.i have searched for that within the simulator_gazebo stack. i only find the spawn_model node,under /opt/ros/electric/stacks/simulator_gazebo/gazebo/scripts question: what is spawn_table?