you can connect a wire to it.
In the base game, the Roboport is one entity that does everything. stores robots, charges them, expands the grid and lets you connect a wire to the roboport to read logistic network contents.
My modular roboports reduce the number of functions to 1, except the robochest that also has a charge pad, because all roboports that allow docking must have a charge pad. (previously, the robots would just queue to wait to charge forever, but now the game won't actually allow you to code it)
Anyway, there's the Logistic zone expander to expand the network, the Robochest to store drones, and the chargepads. Those are pretty obvious, as they're all basic functions.
The LZI just sits inside the logistic network, and lets you hook up a wire to it, so you can read logistic contents.
that's it.
