Samsung have had a feature called WiFi Sharing in their Android devices for some time.
This extends the tethering or hotspot function to be able to share another access point via its own SSID (with the same configuration that'd normally be used for sharing LTE).
How does this work on a low level? Could this function theoretically be added to other Android devices or even AOSP? What features of a WiFi chipset allow this to work?
I see What is the functionality concept behind Wi-Fi sharing (aka Wi-Fi Profile share)? but it only talks about the Android side, not the kernel or hardware side. It's also pretty incorrect as WiFi Sharing (at least on the S8+) doesn't use WiFi Direct at all.