I was one of the few people who bothered to learn how to format numbers and money sums. It used to be, and I thought it was still, like this:
123 456 789,00
123.456.789,00
The first one is a non-money-related number. The second is a money sum.
However, the PHP NumberFormat class (using ICU data, I believe), as well as Windows 10 (at least in the 1903 version) now use this:
123 456 789,00
123 456 789,00
That is, both non-monetary numbers and money sums are formatted in the same way, with spaces for thousands separators and commas for decimal marks.
When I looked in the Windows settings just a couple of years ago, it still used periods for thousands separators for money sums for Sweden.
This must have recently changed and been incorporated into both the ICU data and whatever Microsoft uses for Windows. (I assume that they just use the freely available ICU data as well.)
The problem: I'm trying to determine when exactly this was changed, and maybe even why. Although I guess it's nice in theory that things are simplified and standardized, there is definitely something valuable and interesting about regional differences, and there certainly are a ton of them in many languages/locales/combinations.