What is 'data'?

I see ‘data’ in a lot of code samples. like

terms: [
    {
      field: ['data', 'user']
    },

or

Select(['data','stuff'],Var('zyx'));

as seen in:

Is there a doc page on this ubiquitous piece of code?

Is there a doc page on this ubiquitous piece of code?

Yes, there is a page describing Fauna documents. The data field is described at the bottom, with an example of what a document looks liks.

data is not “code”: it’s a field within a document that contains user-specified fields and their values. That separates user-specified data from the metadata that Fauna needs to store, retrieve, and manage documents.