A range of simple demos for Heat are available at heat.j38.net. By default, these demos point to my Twitch channel, Scott Made This. To point to a channel of your choosing, use one of the following methods.
Clicking the "Browse Overlays" button in the Heat Extension Configuration page on Twitch will automatically append your channel id to the URL.
Alternatively, you can manually pass a numeric channel id as part of the querystring. For example: