Love it! I can see the love put into this.
Snappy, a lot of features. The diff tool seems useful.
The vis tool was neat but I don't often have that need.
I did get it to crash when I dumped a JSON file containing data on every programming language ever made.
Here's my user test: https://news.pub/?try=https://www.youtube.com/embed/ERpyG_f2...