what is Environment <none> in a kubectl describe pod command - kubernetes

Question

When I do a kubectl describe pod, I can see
Environment: <none>
just after secrets. I wonder what it is. Is it possible to assign secrets to an environment? ( local, dev, staging, prod for instance ? )
➜ espace-client git:(master) ✗ kubectl describe pod -n espace-client espace-client-client-6b7b994b4c-gx58t
Name: espace-client-client-6b7b994b4c-gx58t
Namespace: espace-client
Priority: 0
Node: minikube/192.168.0.85
Start Time: Fri, 27 Sep 2019 11:37:06 +0200
Labels: app=espace-client-client
pod-template-hash=6b7b994b4c
Annotations: kubectl.kubernetes.io/restartedAt: 2019-09-27T11:37:06+02:00
Status: Running
IP: 172.17.0.21
IPs: <none>
Controlled By: ReplicaSet/espace-client-client-6b7b994b4c
Containers:
espace-client-client:
Container ID: docker://b3ee1efe45bb8ed9f27aca60e3bfecc1d7e29bc12600787d8d674ffb62ffc3f4
Image: espace_client_client:local
Image ID: docker://sha256:4cf73af7615ebfd30e7a8b0126154fa12b605dd34ead7cb0eefc43cd3ccc869b
Port: 3000/TCP
Host Port: 0/TCP
State: Running
Started: Fri, 27 Sep 2019 11:37:09 +0200
Ready: True
Restart Count: 0
Environment Variables from:
espace-client-client-env Secret Optional: false
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-lzb8h (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-lzb8h:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-lzb8h
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events: <none>

Answer 1

The environment section contains any environment variables defined as part of the PodSpec:
apiVersion: v1
kind: Pod
metadata:
name: envar-demo
labels:
purpose: demonstrate-envars
spec:
containers:
- name: envar-demo-container
image: gcr.io/google-samples/node-hello:1.0
env:
- name: DEMO_GREETING
value: "Hello from the environment"
- name: DEMO_FAREWELL
value: "Such a sweet sorrow"
It is because most likely no Env vars where defined for the Pod. You can also assign Secrets to environment. They would show up in the Environment section like this:
SECURITY_JWT_PRIVATEKEY: <set to the key 'privateKey' in secret 'tokens'> Optional: false
For example:
apiVersion: v1
kind: Pod
metadata:
name: secrets-demo
labels:
purpose: demonstrate-secrets-in-env
spec:
containers:
- name: secret-demo-container
image: gcr.io/google-samples/node-hello:1.0
env:
- name: SECRET_PASSWORD
valueFrom:
secretKeyRef:
name: mysecret
key: password