For the prefix variable here, it might be good to explain that it should not include a leading or trailing slash. Also, it wasn't totally clear to me whether this needed to be the entire path to the WebUI (e.g. `/stages/stage`) or just the last component in the path (`/stage`). In this light the name prefix was bit confusing because it, to me, seemed more like it would mean the former.

It would be good to say it has no slashes and it is the path relative to the parent container. There might also be a more accurate name for this (e.g. `pathComponent`, though I don't really like that one).