What is the Raspberry Pi Pico?

What is the Raspberry Pi Pico?
What are the features of the Raspberry Pi Pico mini development board and the RP2040 MCU chip it uses?

Raspberry Pi Pico is a convenient, flexible and easy-to-use open source electronic prototyping platform. Launched by Raspberry Pi Foundation, unlike any other Raspberry Pi in the past, Raspberry Pi Pico is positioned as a high performance MCU controller, which is dedicated to solve the deficiency of hardware control area that Raspberry Pi is not good enough, and is an important part to make up the functional ecology of Raspberry Pi products.

The main features of Raspberry Pi Pico mini development board and the RP2040 MCU chip used are as follows.
01. Chip adopts 7×7mm QFN-56 package
02. Dual-core ARM Cortex-M0+@133MHz, on-chip PLL allows Core conversion
03. 264KB SRAM and 2MB on-board flash memory on chip
04. Supports up to 16MB of off-chip flash memory via dedicated QSPI bus
05.30 GPIO pins, of which 4 GPIO pins can be used directly as analog inputs
06.2 UARTs
07.2 SPI controllers
08.2 I2C controllers
09.16 PWM channels
10. USB 1.1 host and device support
11. 8 Raspberry Pi programmable I/O (PIO) state machines for custom peripheral support
12. USB mass storage boot mode with UF2 support for drag-and-drop programming