readFile from module mount

I am trying to solve the following with Hugo Modules:

  • Read a file as string from another github repository.

Here’s my module import and mount

[module]
[[module.imports]]
    path="github.com/cibuilds/hugo"
    disable=false
[[module.imports.mounts]]
    source="."
    target="data/docker"

The partial reads the file like this:

{{ $string = readFile "data/docker/build-images.sh" }}

This produces the error

error calling readFile: file "data/docker/build-images.sh" does not exist

With target="content/docker" and readFile "docker/build-images.sh the file is read successfully. However the content folder is surely not the right place for non-content data.

Is this a bug or is readFile not supposed to work with module mounts?