robot_description/scene.xml

<mujoco model="x2n scene">
  <include file="x2w.xml"/>

  <statistic center="0 0 0.6" extent="1.3"/>

  <visual>
    <headlight diffuse="0.5 0.5 0.5" ambient="0.2 0.2 0.2" specular="0.9 0.9 0.9"/>
    <rgba haze="0.15 0.25 0.35 1"/>
    <global azimuth="200" elevation="-20"/>
  </visual>

  <asset>
    <texture type="skybox" builtin="gradient" rgb1="0.3 0.5 0.7" rgb2="0 0 0" width="512" height="3072"/>
    <texture type="2d" name="groundplane" builtin="checker" mark="edge" rgb1="0.3 0.52 0.63" rgb2="0.3 0.52 0.63" markrgb="1 1 1" width="300" height="300"/>
    <material name="groundplane" texture="groundplane" texuniform="true" texrepeat="5 5" reflectance="0.2"/>
  </asset>

  <worldbody>
    <geom name="floor" size="0 0 0.05" type="plane" material="groundplane"/>
  </worldbody>
</mujoco>