When I click on a *.json or *.patch file in Firefox, it asks me what external application I want to view it in.
However, I don't want to use an external application. It's plain text — I just want to view it in-browser.
There doesn't seem to be anything in the UI for this.
Best Answer
Here's an add-on that might help: "Open in browser"
And here's a KB article that also might help, "MimeTypes"