Ah, I see. If you get an error, it helps to show the error. I tried it with 3.8.81:
Invalid number of weights: 0
That is abnormal. I was able to load and view the data with Skeleton Viewer 3.8.99 but it seems that the 3.8.81 and 3.8.99 Spine editor is not able to import the data due to some bug in that old version. Unfortunately it is almost 4 years old and we can't make fixes to such an old version. I'm afraid there is no way to import this binary data. Ideally you have JSON or a .spine file instead, maybe in your backup folder?
