1. Create config directory

sudo mkdir -p /etc/brave/policies/managed/

2. Create policy file

Create /etc/brave/policies/managed/spnego.json with the following contents, editing domain names as needed:

{
  "AuthServerAllowlist" : "*.brainvitamins.net",
  "AuthNegotiateDelegateAllowlist" : "*.brainvitamins.net",
  "EnableAuthNegotiatePort" : true
}

3. Restart

Restart the browser. Verify the policy is active by visiting brave://policy

References