That's got to be it! There's a screenshot with a ramp that looks identical to the one in the vid, just without the signs but it might be an old screenshot because there's an update from 2022 that mentions "brand new custom assets" which might include the signs, either that or they were just added by the video maker with the world editor, not at my pc at the moment so can't confirm right now. EDIT: Just downloaded it and it's definitely the right map, it doesn't have the signs which confirms my second guess that they were added with the world editor for the video. Thanks for finding it!