I'm currently creating a custom launcher that's depending on the version.json, but it has been removed at version 1.13.2
So now we would like to know how to update this (And we know that we "DON'T USE A CUSTOM LAUNCHER", BUT it's neccecery for us)
I think this may be it. I found this in the ~Library/Application Support/Minecraft and it was titled debug.log. I had to unzip it and then it opened into the below text. I believe it to be from one of my download attempts a few days ago.