The whole thing runs off of a Raspberry Pi RP2040 and open-source code. It has modules for NFC, SD card, and Wi-Fi communication, plus it features a miniature display so you can tell what it’s doing. If you want to make your own, the Hackster page features everything you need to know to get started, from the hardware to the code used for the project.
It is open-source and cheaper than the Flipper Zero, so maybe those who held out on a Flipper Zero will find this more appealing.