How to find the document of nnvm IR format

Development pre-RFC
#1 
{
      "op": "conv2d", 
      "name": "conv1", 
      "attrs": {
        "channels": "20", 
        "dilation": "[1, 1]", 
        "groups": "1", 
        "kernel_layout": "OIHW", 
        "kernel_size": "[5, 5]", 
        "layout": "NCHW", 
        "out_layout": "NCHW", 
        "padding": "[0, 0]", 
        "strides": "[1, 1]", 
        "use_bias": "True"
      }, 
      "inputs": [[0, 0, 0], [1, 0, 0], [2, 0, 0]]

i don’t know about what the inputs means here, is there a document i can find all the definitions ? Thanks.