This is a breakout board for the WS2812B RGB LED. The WS2812B (or “NeoPixel”) is actually an RGB LED with a WS2811 built right into the LED. All the necessary pins are broken out to 0.1″ spaced headers for easy bread-boarding. Several of these breakouts can even be chained together to form a display or an addressable string.
Resources
Schematic
Eagle Files
Hookup Guide
All About LEDs
Datasheet(WS2812B)
GitHub(Design Files and Example Code)