The TAJS474M035RNJ: This is a KYOCERA AVX TAJ series molded tantalum capacitor, 0.47 µF at 35 V, in a 1206 (3216 metric) surface-mount package. The ±20% tolerance is standard for tantalum electrolytics — expect the actual value to land anywhere between 0.376 and 0.564 µF at 25 °C, so don't use it where a tighter tolerance timing cap is called for. The 12 Ohm ESR (Equivalent Series Resistance) is on the higher side for a 0.47 µF tantalum in this case size. That means ripple current capability is limited — for a decoupling cap on a 35 V rail with a few mA of ripple, it's fine. But if you're using it as an output filter on a switching regulator, the I²R losses will heat the part, and the self-heating eats into the 125 °C temperature margin.
A 35 V rating at 125 °C means the voltage derating is already baked in — you can run it at 35 V across the whole temperature range without further derating, though many design guidelines recommend staying at 2/3 of rated voltage for tantalum reliability.