Custom Nuget Package Not Copying Files

Question

Trying to create a nuget package for consumption by a legacy project. The package should simply add a directory and some binary files to a solution. The files should be added to the project directory, not the bin/output directory.

I am using a nuspec file and the nuget pack command to create the package.

The files get added to the package successfully, but when installing the package, everything succeeds but the folder and files don't get added.

Reading the docs, it doesn't appear that a powershell script is required for this type of action, but I can't seem to find a clear answer.

This is for a .Net Core 3.x project if it matters.

My most recent nuspec file is below. I have tried using a files tag, a contentFiles tag, and a combo both.

<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata>
        <!-- Required elements-->
        <id>My.Project.Id</id>
        <title>My title</title>
        <version>1.0.0</version>
        <description>Here are some files.</description>
        <authors>me</authors>   
        <contentFiles>
            <files include="**/**" buildAction="None" copyToOutput="false" />
        </contentFiles>
    </metadata>   
</package>```