Comment by teraflop
Almost.
For one thing, Docker is not really "Linux inside Linux". It uses Linux kernel features to isolate the processes inside a container from those outside. But there is only one Linux kernel which is shared by both the container and its host (within the Linux VM, in this case).
For another, running Linux containers in a Linux VM on Windows is one (common) way that Docker can work. But it also supports running Windows containers on Windows, and in that case, the Windows kernel is shared just like in the Linux case. So Docker is not exactly "Linux tech".
I think GP is likely referring to Docker Desktop, which is probably the most common way to use Docker on Windows.
Running Linux containers using Docker Desktop has a small Linux VM in which the containers are run and then Docker does some mucking about to integrate that better with the Windows host OS.