Leaked images published by HDblog.it suggest that the ZenFone 6 might have a notch towards right of the screen instead of the usual center.
While it looks like a prototype due to the shabby build quality, but it is fully working.

The notch sits between the battery and other icons on the far right, while a very small bezel at the top has the integrated earpiece.
There is also a 3.5 mm headphone jack slot.
The ZenPhone 6 is expected to be announced at MWC 2019 to be held in Barcelona, Spain.