It’s just a hunk of plastic with some o-rings in the rough shape of a water filter. It would be used in place of the water filter. It has a special rfid in it that the fridge just says ‘bypassed’ on it for the filter life.

There are many sites that show people extracting said rfid from the bypass and dismantling the water filter holder and taping the rfid right onto the reader. Then using whatever the heck filter they want for as long as they want.

My fridge came with a bypass right out of the box. Didn’t know any of the rfid junk existed until it just wouldn’t dispense water anymore a few months later. It probably never dispensed more than a gallon or two. So the filter was absolutely fine. The fridge does it purely off time and nothing else. Mind you the fridge has a precision pour feature and counts the dispensed ounces every time you use it. So it could absolutely do it by actual water filtered but that wouldn’t be as profitable.

I already had an RO system under my sink. Just ended up plumbing that into the fridge water line and using the bypass. Been several years now, no issues.