I am surprised the lack of mention of Denmark, Sweden or the Netherlands. Most business persons I contact, normally only work 4 days a week.
That said, some of the last few weeks at the time of writing have in practise turned out to be four day weeks due to public holidays. Could this be what causes the confusion?
I work in SWE, which is almost always 40 hours in my experience YMMV.
This, however, is not the same as an entire company working 4 day weeks.
Whereas in the Netherlands, Switzerland, Scandinavian countries, etc. they typically accept 32 or 24 hours but with a proportional pay cut.
What we really should be trying to normalize is most everything shutting down an extra day where possible.
Or you can have a true 4 days/week. With the pay cut. As for half time and so on… taxes though start to rise, because why not.
I hate so very much my government for this kind of shit.
Externally it might seem like 4 days a week, but its actually 5 with one where you can't reach them.