Docker Bake Sub-Action: Do I need a follow-up step to recombine architectures for the multi-arch manifest?

[avosepp]

I'm looking at this documentation: https://github.com/docker/bake-action/tree/master/subaction/matrix

The bottom section gives the example for Platform Split builds, which is exactly what I'm trying to do. Build ARM and x86 images on their respective GitHub Actions runner type.

But it feels like this example is missing something. At the end I believe I need to upload a multi-arch manifest so tools like Kubernetes can correctly pull the right architecture. I'm looking for a little insight. Is that needed, or is there some magic happening behind the scenes? If it is needed, what is a clean way to go about doing that?

Thanks!