Are grad and data properties of Tensor?

I have seen a lot of examples that for tensor x they use x.grad or for parameter (a subclass of tensor) they use param.data.

Are these two properties of Tensor? If they are why can’t I find, for example grad, in TORCH.TENSOR properties?

You can find the docs for torch.tensor.grad here.
I wouldn’t recommend to use .data, but instead wrap your code in a torch.no_grad() block, if you would like to manipulate the data:

with torch.no_grad():
    module.weight[0, 0] = 1