Maybe you are right. I have opened the JSON file, and I cannot find my private key. However, I do see signatures and other items that I do not understand. That was the reason for my question. However, I took the gamble and backed it up to the cloud already without encryption... 

 I'm sure now, definitely no private key. I don't understand much about the signatures either but the signatures are always public on the nostr relays too as I understand it. Good of you to open up the file and check it out 🤙