This node is created the first time Profile Lines is set to the Offset Mesh option (see Profile Lines in the pfxToonShape node). The pfxToonProfileShader is simply a surface shader and has a solid color. The outColor of the pfxToon node connects to the outColor of this surface shader so that updating and texturing the profile line color will also affect this shader. If you change the Profile Lines type back to Paint Effects or turn it off, the added shader and mesh nodes will still exist, but will have no effect because the output meshes will have no triangles.