There is no confusion. It has x16 lanes for graphics/slots, x4 dedicated lanes for NVMe storage, and x4 lanes for the chipset.
The chipset multiplexes up to x16 lanes of "stuff" onto the x4 chipset lanes from the CPU.
All of this is physically determined by the pinout of the socket and none of this can change unless AMD moves to a new socket. What did change is the speed of the lanes - x4 lanes on 4.0 is twice as fast as x4 lanes on 3.0.
AMD, like Intel, likes to pretend that chipset lanes "count" as full CPU lanes, arriving at a total of 36 effective lanes. But that's nothing new either.
That's correct, however, considering that Zen 2 supports PCI-E 4.0, that's double the bandwidth of the previous generation, it means that those multiplexed 4x can theoretically now support double the bandwidth of the previous generation 4x and it's not like the "stuff" that does get multiplexed over that 4x (USB, SATA, some 1x cards like sound, wifi and ethernet) also suddenly needs twice the bandwidth meaning that in practice, that 4x works as an 8x in Zen 2 motherboards. Great deal I say :)
The chipset multiplexes up to x16 lanes of "stuff" onto the x4 chipset lanes from the CPU.
All of this is physically determined by the pinout of the socket and none of this can change unless AMD moves to a new socket. What did change is the speed of the lanes - x4 lanes on 4.0 is twice as fast as x4 lanes on 3.0.
AMD, like Intel, likes to pretend that chipset lanes "count" as full CPU lanes, arriving at a total of 36 effective lanes. But that's nothing new either.
https://www.techpowerup.com/img/PXQ4X5jG1JfBexk6.jpg
https://www.techpowerup.com/img/HMRSMmd3jbU2CVX0.jpg