I have also tested ESP8266_LIGHT_WITH_MESH demo on my ESP-WROOM-02 Wifi Module but not found actual MESH Network related functionalities which I am thinking.
MESH Network is one type of network in which one ESP Device becomes as Root Node which is directly connected with external network router and all other ESP nodes are connected with nearby shortest path node.
so that each child node can reach to Root Node and can post data to cloud through external router.
Regards,
Ritesh Prajapati