I have Samsung Galaxy S7 running on Android 7.0 Nougat. I got a new notification symbol that looks like a white rectangle on the right side (which is usually for system icons).
Sometimes it's gone while I'm browsing with the Chrome browser but then it's back.
I don't use or install any Cast apps. Long-pressing the icon only open the notification bar, but no additional information. Toggling GPS, NFC, Bluetooth didn't help.
What does this icon represent?