The main chip on board is the 'RP2040' made by Raspberry Pi (their first in-house microcontroller chip!) and is a dual-core ARM Cortex M0+ processor, with a flexible clock running up to 133MHz.
RP2040 microcontroller chip designed by Raspberry Pi in the United Kingdom
Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz
264kB of SRAM, and 2MB of onboard Flash memory
Castellated module allows soldering directly to carrier boards
USB 1.1 Host and Device support
Low-power sleep and dormant modes
Drag & drop programming using mass storage over USB