With '19 it was part of the Premium Package, which was far too good of a deal to not buy...
$1400 for the following:
2 zone automatic climate with clean zone
8 way power passenger seat with 4 way lumbar
Heated windscreen wiper blades
Power Child Lock rear doors
Pilot Assist andAdaptive cruise
Removable/folding lad floor
Homelink and compass mirror
Power folding rear backrest and power headrest
Interior High Level Illumination
Keyless Entry with Hands free tailgate
Wireless charging for smart phones
Hidden storage compartment under drivers seat..>
Again... $1400 for all that. I know inventory was tight last year so many folks got what they could, but IDK why a dealer wouldn't order that on every car. I had one customer customize their car without this on an order despite my trying to convince them to get it, never made sense to me.
For 2020 it gets a bit more costly to add as it's part of the Advanced Package which requires other packages. Still, many customers don't really need lighting for the back seats. IMO not the worst thing Volvo doesn't make standard, but I would be more forgiving of it if it was in the Convenience package or something nearly standard like that.
If you are leasing, never modify your vehicle with non authorized accessories or you will be charged for damages. This means if it's not Volvo, don't add it. They might miss it in inspection, but per the contract you would be liable for replacing the whole headliner and wiring harness if you had someone cut and splice a solution into it.