Well, it's due to the sudden disconnection (dumping) of a heavy load -- the battery most of all given its charging capacity, and then also exacerbated by other changes in load, say turning off the headlights or whatever. One of those very context-dependent terms; it says what it is, if you know everything about the situation (automotive, conventional regulated alternator, battery disconnect), but if you're missing those pieces and take it at face value, yeah, it's not too helpful really. Anyway, for better or worse, this is the accepted terminology in the English speaking world. English being what it is, well, this is just par for the course honestly...
Also, it's... not strictly overvoltage protection, as one might argue that -- well, if it's over
voltage, it's simply, whatever the applied voltage is, there you have it; you'll just footgun yourself trying to shunt it, voltage is voltage. So you still need to see the definition. And as it happens, this is defined to have some source resistance, so shunting isn't actually futile, just difficult. Example: jump starting 2x voltage is another common automotive standard, and that happens with very low source resistance; you have no choice but to ride through or shut off (including by fuse) under such a condition.
And "surge" maybe isn't a great term, it's a general word but the most common kind of surge (without qualifiers) is understood as a lightning-induced type, of the 1.5/50 to 8/20 to 10/1000 µs waveforms; these do define source impedances, and the general waveform isn't very different (sharp rise, slow fall), so, to be fair it's not terrible, there's just the particularity about how the DC is wired in (it's diode-OR'd), and it would just be a little odd to say a 80V 1,000/100,000 surge. Though honestly, I'm kind of liking the generality, just make sure you don't leave off the units so it's very obvious it is in fact 1/100 ms or whatever.
Tim