It's like kicking in an open door, however, it never was confirmed. Z490 motherboards are designed for the announce Comet Lake-S processors, but of course will also support the following proc series, Rocket Lake.
That however never was confirmed, However, Gigabyte in an Aorus live stream slipped the word out and confirmed it. And it's important to know as Z490 motherboards are PCIe Gen 4.0 compatible, just not with Comet Lake, but with Rocket Lake processors. Rocket Lake (RKL) is a planned microarchitecture designed by Intel as a successor to Comet Lake for desktops and high-performance mobile devices, based on 14 nm fabrication.
Gigabyte Aorus confirms, Rocket Lake will also work on Z490 motherboards
