BIOSTAR has accidentally leaked out Intel's upcoming Z390 chipset, with an early reveal of their own Z390 RACING GT3 and GT5 motherboards with a manual on the B360 RACING GT3S leaking and teasing the Z390 as well.
If we're seeing manuals on these motherboards, it means that the new/refreshed Z390 motherboards are imminent. The manual can even be downloaded from BIOSTAR's website, but we don't know much about the Z390 chipset at all. We do know that BIOSTAR's new motherboard has support for CPUs at up to 95W TDP, which might "indirectly confirm the maximum TDP of 8-core Coffee Lake-S CPU" according to VideoCardz.