Yeah it's the one mentioned in the article. I've tried FreeRouting or whatever it's called before and had... ok results... but it's a pain in the ass to set up. This KiCadRoutingTools code was super easy to set up in comparison.

Edit: actually, one interesting thing to consider about routing vs. schematic design: my general experience with LLMs is that things work best when there's a feedback loop. On the schematic side, there isn't really much of a feedback loop; nothing will tell you that you've e.g. flipped the + and - terminals of your Opamp.

On the layout side, you've got the ratsnest and DRC to tell you whether you're winning or not. That might be the key to making LLM-based routing work. Opus refused to hand-route my whole board yesterday but is currently using the KCRT tools to do the routing and things seem to be progressing well.