Interesting, thanks!

How do they do that without sending your actual passwords somewhere off your device, or downloading the full list of hacked passwords?

I think you’re missing something here; in the UK we also talk about pre-tax income.

It’s important in lots of ways, for example you choose how much to pay into your pension, and you get tax relief on that.

If you just talk about post-tax income you would miss the enormous difference between someone who is on £54,350 and pays the minimum 8% into a pension (£50k taxable) and someone on £62,500 who pays 20% into a pension (£50k taxable). The second person is a lot better off overall, because they have saved £12,500 in their pension and the first person has saved £4,350, which compounds pretty quickly.