It's a Betaflight flight controller, designed by Joshua Bardwell. The Bardwell f4 AIO, by RaceDayQuads.
✓ 3-6s F4, AIO board with MPU 6000 gyro
✓ Superb board layout allowing for easy and clean builds
✓ Joshua Bardwell authored manual and selected features, manufactured and backed by RaceDayQuads
✓ Centrally located gyro
✓ Betaflight OSD w/131a current sensor
✓ Compact 30.5x30.5 board layout
✓ 7.6v filtered power out for VTXs – very strong filtering capability for clean video (the 5v output is also filtered)
✓ Power Out: 3x 5v, 1x 3.3v, 1x VBAT, 1x VTX filtered power (7.6v), 1x Camera filtered power (7.6v);
✓ 4x UARTS for FRSKY, SBUS, IBUS, SAT (2 inverted UARTS)
✓ Smart Audio compatibility and Camera Control capability
✓ Pre-flashed with BF 3.2.1 – Compatible with CLRACINGF4.hex
✓ Programmable LED pin
✓ Buzzer pins
✓ Blackbox capability
✓ No pinned-connectors – all direct solder for optimal durability
✓ Included and installed vibration dampeners