I'm trying to save the contents of a configmap to a file on my local hard drive. Kubectl supports selecting with JSONPath but I can't find the expression I need to select just the file contents.

The configmap was created using the command

kubectl create configmap my-configmap --from-file=my.configmap.json=my.file.json

When I run

kubectl describe configmap my-configmap

I see the following output:

Name:         my-configmap 
Namespace:    default 
Labels:       <none> 
Annotations:  <none>

Data
==== 
my.file.json:
---- 
{
    "key": "value" 
} 
Events:  <none>

The furthest I've gotten so selecting only the file contents is this:

 kubectl get configmap my-configmap -o jsonpath="{.data}"

Which outputs

map[my.file.json:{
    "key": "value"
}]

The output that I want is

{
  "key": "value"
}

What is the last piece of the JSONPath puzzle?