Which API returns the 'subproject of' field for all existing projects?

api/v3/projects

The HalResource for every Project returned has a parent link.

HalResource {
  _uri: URI { uri: '/api/v3/projects/28', templated: false, fetchedURI: '' },
  links: {
    categories: HalResource {
      ...
    },
    delete: [Circular],
    schema: HalResource {
      ...
    },
    parent: HalResource {
      _uri: [URI],
      links: [Object],
      props: [Object],
      isLoaded: true,
      settedProps: [Array],
      settedLinks: [],
      initEnded: true,
      restClient: [HalRestClient]
    }
  },
  props: {
    ...
  }
  ...
]

Which API returns the 'subproject of' field for all existing projects?

I need the field - subproject of

Please**.**

Julio

OK.

In version 7 don't work. Tks.