pull down to refresh

Yep, that’s ours.
We host the .dmg on https://downloadmacos.com to keep the file delivery fast and signed from a domain we control (GitHub's CDN had some issues with visibility in certain regions). The build itself is fully open-source and reproducible - the exact source code is on GitHub.
As for the Secure Enclave - yeah, Apple actually exposes a really nice interface for it through CryptoKit. It’s limited (by design), but more than enough to generate and safely seal a Bitcoin key inside the chip. You just can’t get the key back out, which is kind of the point :)
Let me know if you want a walkthrough or want to poke at the code - happy to dive deeper.