Electronics need sensors to gain clues about the physical world. Adafruit is developing a new board called Clue, which comes with (almost) every sensor type you might want to use. In addition to being an all-in-one sensing platform, the Clue's form factor, size, and pin-compatibility make it a spiritual successor to the BBC micro:bit.
When developing the Clue, Adafruit needed a board larger than their Feather form factor but not as big as their Metro boards to fit all of the sensors. Instead of developing a new board size, they adopted the micro:bit's shape, size, and pin-out. This choice means the Clue is compatible with existing micro:bit cases and accessories, while adding new capabilities.
The Clue's nRF52840 Cortex-M4 is a significant upgrade compared to the micro:bit's M0-based processor. The M4 is the same BLE-enabled processor used on other Adafruit boards, like the Circuit Playground, so expect Arduino IDE compatibility and extensive CircuitPython support. Adafruit estimates support for Microsoft's MakeCode will take about a year.