I just downloaded the HTML file pack, unzipped it into a directory where I keep a lot of ancillary OBS tools, then created a web panel to load this page.  Reason:  I use a two-OBS setup, one on one computer to capture and composite, sending the resulting video via NDI to a second, which does the actual encoding and streaming.  I also have Websockets installed on the encoder/streamer OBS instance, to which I point your page via the abovementioned web panel in the streaming OBS setup.  That way I can make sure the right scenes are selected in case something goes wrong with the Advanced Scene Switcher process I use for most of the automation I do, which includes making sure the NDI ingestion scene is actually visible when I need it to be.
Thanks so much for this.  I wanted something super simple yet didn't need something needlessly complete like TouchPortal or LioranBoard (which I really only use with the studio PC).  This is perfect for this purpose!