How do the configuration_parameters in vsphere-iso builder work?

How do the configuration_parameters in vsphere-iso builder work? The documentation says:

configuration_parameters is a direct passthrough to the VSphere API’s ConfigSpec: https://pubs.vmware.com/vi3/sdk/ReferenceGuide/vim.vm.ConfigSpec.html

First of all, the link is broken. I found something, that should also work: https://code.vmware.com/apis/358/vsphere/doc/vim.vm.ConfigSpec.html

However, it does not work as I would assume.

Adding a key-value pair "nestedHVEnabled": true should add vhv.allow = TRUE to the vmx file. Instead it literally adds nestedHVEnabled = TRUE. Same with "changeTrackingEnabled": true, which should add ctkEnabled = TRUE to the vmx, but instead adds changeTrackingEnabled = TRUE to the vmx.

On the other hand, the API docs don’t list any option to set the vmx option svga.autodetect = TRUE, but adding the key-value pair "svga.autodetect": true to the configuration_parameters does add it to the vmx file.

Looking at the docs, shouldn’t I have to use the extraConfig API property for things like svga.autodetect?

Okay, then I tried to add the following four settings:

"configuration_parameters": {
    "vhv.enable": true,
    "uefi.secureBoot.enabled": true,
    "vvtd.enable": true,
    "windows.vbs.enabled": true,
    ...
    "svga.autodetect": true
}

The none of those settings are written into my vmx file, while svga.autodetect is.

I’m completely confused.