Re: Concerns on the "unique_id" in the service metadata
1. The value of unique_id is a guid. We have submitted this PR https://github.com/adowns01/docs-services/pull/1 to the documentation team so that they can clarify this in the example you pointed out.
2. As far as we know, there's no particular reason why the unique_id was not presented in the spaces summary.
Amelia and Urvashi, CAPI Team Members