"A modified version of OpenHaystack to showcase the possibility of building a stealth AirTag clone that bypasses all of Apple's tracking protection features."
Impressive. Here is the blog post (also linked from their github) that talks about the bypass (the tldr; is that they rotate through public keys in a deterministic way, so Apple’s protections think it’s a new device each time and thus don’t warn about a persistent tracker).
https://positive.security/blog/find-you