Ok, RoepStoep, I understood that before integrating the code into the website, you have to use the back button ⏮ to bring the position to the start. So, we get # 0 at the end of the code.

Indeed, you get the code for an ambedded board that starts at the position you're currently viewing. The hash in the url is just the ply, so it's also easy to edit manually.