Environment Variables cannot be accessed

[Vonor]

Apparently in VS Code you can use ${env:SOMEVAR} to use the environment variable's content.
However, in a powerHeader template setup I am trying the following:

settings.json

    "powerHeader.variables": [
      "<author>=\"${env:USERFN}\"",
    ],
    "powerHeader.template": "Author: <author>"

Upon inserting the header into a new file I get

Author: USERFN

This seems to be a bug in my opinion. Or is there another way of doing that, which I couldn't find in the documentation?

[paepcke]

This non-interpretation of env vars is particularly problematic when templates are stored, say, in $HOME/.vscode to be accessible from all projects. I tried:
o "File:///${env:HOME}/.vscode/javascriptSuperHeader.template"**
=> /ENOENT: no such file or directory, open '/HOME/.vscode/javascriptSuperHeader.template'/

o "${env:HOME}/.vscode/javascriptSuperHeader.template"
=> /HOME/.vscode/javascriptSuperHeader.template/

Absolute paths work. But that approach won't work across machines (e.g. MacOS/Linux