A presentation about Fuelino Proto2 is available here: Fuelino Proto2 Presentation.
The board is capable to control 2 fuel injectors, through 2 FKI10531 MOSFETs. When closing the injectors, the voltage is clamped using 2 networks made by 4x 12V Zener diodes in series (one network for each injector). Input signals are acquired using LM358N (2x analog signals, 0-5V) and LM339N (4x digital signals) operational amplifiers.
The board has 1x UART connection, which is handled by software using SWseriale library, available on GitHub. This port can be used to communicate, for example, with a GPS module (such as Ublox Neo 6M or similar) at 9600 baud, or a Bluetooth module.