What this part is — triple unbuffered inverter from the 74AHC family
The 74AHC3GU04DC-Q100125 is a triple unbuffered inverter from Nexperia's 74AHC series. It contains three independent inverter gates, each with a single input, in a surface-mount package measuring 2.30 mm wide. The unbuffered output stage means the propagation delay and output drive are lower than a standard buffered gate, which can be an advantage in oscillator or linear-mode circuits where you want the gate to operate in its linear region.
The Q100 suffix confirms AEC-Q100 qualification, which also means the part has been through extended reliability testing (high-temperature operating life, temperature cycling, etc.) — a useful signal even for non-automotive designs that want a proven part.