Using Material Input Node - Warwlock/blender-nodes-subgraph GitHub Wiki
Material Input Node
Port Name
In port name, you can only write letters and numbers (You can't write a number in start).
Adding a Port
First be sure there is no same name with other ports.
When you click to Add Port a dropdown appears. Select a type for usage.
Removing Port
Click to Remove Port and then select port name you want to remove.