How do you pass more / custom parameters to the customer bind / private data in knockout

So this is an extension of this question

Magento 2.3 display logged in/out message using private content

Default behavior is that data-bind="scope: 'customer' has a few properties

eg

data_id: 1234567890 firstname: "Dominic" fullname: "Dominic Xigen" websiteId: "1" 

I’m looking for an example on how to pass other or custom customer attributes to knockout.