The article describes hosting a full static website on an 8-bit microcontroller (ATmega1284P) with custom TCP/IP stack, Ethernet controller, and SD card storage, achieving basic web serving with extremely limited hardware resources.
An AVR64DD32 microcontroller (8-bit, $1, 64 kB flash) was turned into a web server using SLIP over a USB serial adapter and a wired Ethernet-like connection to a Linux machine. Custom minimal TCP/IP and a hardcoded HTTP response allow it to serve a single page, which is proxied over WireGuard to a public VPS for internet access.