Documentation for 'comprise'

[cefn]

In #6 (comment) I note the inclusion of the extra word 'comprise' for request assertion chains.

I can't find documentation for this keyword through an API search or elsewhere on the web.

It may be because one of the unfortunate costs of building sentence-like build chains - is that each function is a dictionary word not a distinctive compound name and is therefore hard to google, so sorry if I've missed some documentation somewhere.

Without a definition of the intent of 'comprise' I am struggling to know, for example whether I should expect a tree like...

{
  root:{
    branches:[
      {
        leaves:['leaf0','leaf1','leaf2']
      },
      {
        leaves:['leaf3','leaf4']
      }
    ]
  }
}

...would comprise of...

{
  root:{
    branches:[
      {
        leaves:['leaf3']
      }
    ]
  }
}