The DevTools Challenger page is meant to be a more hands-on set of exercises to familiarize people with the new / improved animation tools. You should be able to complete it in regular Firefox (or even Chrome), but the experience will be a bit nicer in DevEdition.
An add-on crashing Firefox is definitely a bug on our end, even if it's also a bug in the add-on. :) I've filed https://bugzilla.mozilla.org/show_bug.cgi?id=1221273 to track this, but I can't reproduce the crash myself. The page doesn't use React, FWIW.
If you could stop by that bug and leave a comment with your OS, Firefox version, and build info from about:support, I'd appreciate it.
The DevTools Challenger page is meant to be a more hands-on set of exercises to familiarize people with the new / improved animation tools. You should be able to complete it in regular Firefox (or even Chrome), but the experience will be a bit nicer in DevEdition.