Questions in the dataset of the meshgraphnet

I have some questions about the data structure of the meshgraphnet, especially for CylinderFlow and Airfoil:
cells: [num_steps, num_nodes, num_dimensions(3, triangular mesh is combined with three nodes)]
mesh-pos: [num_steps, num_nodes, num_dimensions(2)]
node_type: [num_steps, num_nodes, num_dimensions(1)]
velocity: [num_steps, num_nodes, num_dimensions(2, x-direction velocity and y-direction velocity of each node)]
pressure: [num_steps, num_nodes, num_dimensions(1, the pressure of each node)]

I can't make sure my understanding of your dataset is true. So, if my understanding is wrong, please point it out. Thanks.

There are still some questions else existing.

For the node_type: can you explain the node type carefully? such as the meaning of NORMAL, OBSTACLE, AIRFOIL, HANDLE, INFLOW, OUTFLOW, WALL_BOUNDARY and SIZE?
The data of the velocity and pressure is the node's velocity and pressure, not the grid's, is it?
Looking forward to your reply. Thanks.