Editing "Persist" Files

[Aven]

I like to tweak game files here and there - I'm not skilled enough to actually do any modding, but I've figured out some fun stuff to mess around with. I just use my PC's default Notepad app to edit the .json files, and it usually works just fine.
However, I found that I couldn't read any of the "persist" .json files. e.g. persist.game.json, persist.estate.json, etc. They are located in steam folder\userdata\user ID\262060\remote\profile
I open the file and it's just a bunch of gibberish - looks like an encoding problem. I've since downloaded some other text editors like Notepad++ and Sublime text, but none could read them either.
Any help appreciated :D