If you don't want to set up a build environment, you can download Hyperapp Debug from a CDN like unpkg.com, and it will be globally available through the window['hyperapp-debug'].default object. hyperapp-debug supports all ES5-compliant browsers, including Internet Explorer 10 and above.
Probably not 100% accurate anymore, since it's es5-compliant, but only Firefox (and Chrome) are supported for the extension.
Probably not 100% accurate anymore, since it's es5-compliant, but only Firefox (and Chrome) are supported for the extension.