Change .pth to .ptl

I have a .pth file, how can i change to .ptl?

Could you explain what these files contain? I assume the .pth file stored PyTorch state_dicts?

The .pth file stored PyTorch OrderedDict

In this case it seems the .pth file was created via, "PATH.pth"). What is the .ptl file supposed to contain? I assume it should differ in a way?