Version 2.3 of the SE API does not clearly distinguish between questions that are on Stack Overflow's Staging Ground and questions on its main site. This comment on a SmokeDetector GH issue details it pretty completely, but to recap, GET requests for SG questions currently look something like this:

"items": [
  {
    "score": 0,
    "creation_date": 1725590314,
    "post_type": "question",
    "post_id": 78955432,
    "share_link": "https://stackoverflow.com/q/78955432",
    "link": "https://stackoverflow.com/q/78955432"
  }
],

This is nearly identical to the regular report for questions, which makes it difficult to tell whether a post is an actual question or not.

How can I access information about a post's Staging Ground status via the API?