Why? I often need to debug fairly large json files (10MB+). For a time I used a combination of JQ in the terminal for filtering and Firefox native viewer for full text search. Then I had an epiphany "Wait a sec, I am a developer! How hard could it be to combine those features in a single product?". Harder than I expected (of course), but still, here we are.

Disclaimer: I'm a backend developer by day, no designers were harmed in the making of the UI/UX :)