No, it's just as the parent describes: A Thunderbolt-to-PCIe bridge chip, a short PCIe connection, a PCIe Firewire host chip, and a microcontroller to coordinate.
I have fixed my post to not imply it's only a single chip. It being multiple important chips should cause the opposite of amazement. It means that the product wasn't important enough to get a dedicated chip, which is probably the main reason it costs $29 instead of also being $9.
https://forums.macrumors.com/threads/apple-thunderbolt-to-fi...