Enforcing Youtube Strict or Moderate mode
In the local policy, add a new entry:
Entry: youtube.com (with no https://)
Entry type: URL
Request Part: Request URL
Action: Modify Header
In the Add or Replace field, add: Youtube-Restrict: Strict or Youtube-Restrict: Moderate
Click SAVE ENTRY
Create a shared list called "Youtube Allow" and add a new entry:
Entry: https://youtube.com
Entry type: URL
Request Part: Request URL
Action: Allow
Click SAVE ENTRY
Attached the shared list to the local policy.