An organization in Portland, OR, called Hacienda Community Development Corp. – “a nonprofit that develops affordable housing and helps people become homeowners” – just instituted a policy whereby their office will be closed on Fridays. And that's not a “going from 5×8 hours to 4×10 hours” thing. It's a “going from 5×8 hours to 4×8 hours with no reduction in pay” thing.
They made this change hoping that it will “aid staff productivity, well-being and retention”, citing a 2021 study in Iceland that observed how, with a four-day week, “worker well-being increased across a range of indicators, from perceived stress and burnout, to health and work-life balance.”