Mine does from 2016, but was it not deleted from about MY21?

with bigger battery in came a larger up front e motor instead of supercharger, some manufacturers like Audi call this bigger front motor an e supercharger, perhaps Volvo have done the same in marketing speak?

Again my understanding is the previous T8 had about 400bhp, where as the latest T8 has as we know 450bhp. Th extra is due to the increase in output from the electric motor.
But I stand to be corrected if I am wrong.

Yes you are correct, the newer T8's (Turbo only) have actually lost approx 10hp on the ICE alone but gained 58hp with the improved electric motor in the ERAD. The E-Boost starter/generator that is incorporated in with the ICE and gearbox (to provide torque fill in place of the supercharger) has the same power (90hp) as the older T8's ERAD has so overall the newer T8's feel much quicker than the older twincharged cars did and ditching the supercharger really did improve efficiency.

So now I am confused....

Old T8s. 320bhp ICE up front with turbo and supercharger. 87bhp ERAD at back. 407bhp total. Starter generator used to charge batteries and start engine (which is located under bonnet).

New T8s. 310bhp ICE with turbo I understand, but then I get lost with how it becomes 455bhp. Does the starter generator now operate as a boost for the engine aswell as starting it and charging the batteries?

I've checked the tech specs on some older price lists.

That's correct.

MY24: ICE output 310hp, electric 145hp making 455hp total.
It's unclear whether the additional electric power comes solely from the ERAD or is partly from the SG.

Curiously, for MY21 the figures are ICE 303hp and electric 87hp making 390hp. Maybe the 'missing' 17hp from previous specs is the removal of the supercharger?

Supercharger on old cars wasn't really used for power but low down torque whilst turbo span up, this fill in can now be done with the e motors. ISG does do assist also.

Handy image of latest setup

https://i.postimg.cc/cLFjpBNc/volvo-t8-powertrain.webp

Same here. Ordered XC60 T8 12 September, est del was mid Dec, then amended to end Jan or Feb a month ago. Now, (after much pressure for info from me directly with Volvo) another 7 months, ie August. Unacceptable, but if it is due to parts on back order why don't they say? Now cancelled, and found a 6 month old T8 with collection next week.

Your MY21 car still has the supercharger, the change to Turbo only came at the time the 'Extended Range' drivetrain with 18.8kwh batteries was introduced sometime in mid/late 2022.
For some reason between MY20 and MY21, Volvo reduced the T8 ICE output (quite likely an emissions thing) but I believe the additional output could be regained by getting the Polestar Optimisation software put on it.
My MY20 Polestar Engineered ICE produced nearly 340hp with a combined power of 420hp but I think the MY21 Polestar Engineered only had 405hp same as the MY21 T8 with Polestar Optimised software.

Yes it does and it does a really good job of it too.
I was worried when swapping my car to the newer drivetrain and loosing the supercharger as I was expecting it to be a little laggy on pickup but the responsiveness of the newer drivetrain is superb, especially when driving it in Power/Polestar Engineered mode.
When going for an overtake, the rate at which it responds and accelerates can sometimes catch you out and you almost have to swerve around the car you are overtaking as it surges forward.