I dont think it is? https://alec.is/posts/ip-crawl-exposing-the-massive-open-web...
Edit: they're literally the same image
2fc4ad21cfce564f7aa65942eae7d4529c8af3d7ffb6287aa1fd79ebb78eb648 ipcrawl.jpg
2fc4ad21cfce564f7aa65942eae7d4529c8af3d7ffb6287aa1fd79ebb78eb648 shodan.jpg
If a subsequent probe fails, the system cross-references threat intelligence platforms like Shodan to match the host and falls back to their specific indexing methods.
So it uses Shodan, but is not purely a mirror.