tl;dr: Device tree files in Raspberry Pi's Linux kernel have revealed two unannounced boards: a Zero 3 W and a Pi 4 Model A, both using the Broadcom BCM2711 (quad-core Cortex-A72) from the Pi 4. The Zero 3 W would be a significant upgrade over the Zero 2 W's A53 chip, while the 4 Model A appears to be a stripped-down Pi 4 (no Ethernet, single HDMI, no analog audio) with possible external antenna switching. Pricing, RAM, and release dates remain unknown, though kernel support typically signals an imminent launch.