I don't know, but several people I know have been using them without issue for over a year, and I've had no problems in the last several months. Every night, I pile up a bunch of devices on the kitchen counter and charge them overnight. Usually, it's an iPhone with a USB-C port, an iPad Pro 12.9 M1, and a misc device, like a Switch or Kindle Paperwhite.
The only things I don't plug into it are my MacBook Pro 16 M2 (work) and our 15" MacBook Air M3 (personal). Those go to dedicated chargers, though not necessarily Apple ones. I keep an old Lenovo laptop USB-C charger in the kitchen while working outside our home office. When we both have conference calls, I run upstairs, grab it, and plug it in at the kitchen or dining room table.
The laptops never worked with the magnetic cables I used to use, so I don't trust them to charge reliably on these cables, but all less powerful devices charge without a problem. However, they split the current since it comes from one USB port in the kitchen outlet or a 100w travel charger plugged into a hotel outlet.