What does the results NPZ file contain?

[malay-gaherwar]

I take the case of short term traffic forecasting like AGCRN. I see that the test_results.npz file generated contains 3 numpy arrays: prediction, target and inputs. All of them of the dimenions of the test dataset with input or output length included in them. Lets say the number of time steps of the test dataset was 21000 and number of sensors were 400. My target array should be of dimensions (21000,400,1), where 1 indicates traffic volume. But instead the dimension of all these 3 arrays is (21000,400,12,1). My questions are as follows:

1. What does 12 indicate?
2. How can I get the dates back? The input data had exact dates associated with each sensor and traffic volume.
3. What is inputs here? If it is training or validation set then it doesn't make sense for it to be 21000 in size cause both training and validation were bigger. If it is test data then whats the difference between target and inputs?