Summary

We would like to implement complete Confluence page rendering in our Confluence Cloud add-on (render page in add-on's iframe). Like Jira Service Desk Knowledge Base does (please see the screen): https://www.evernote.com/l/AQGNAv0UVnhF9JicXM3rPDCnYpgCwWj3h2I
But it is necessary to whitelist Confluence endpoint /plugins/servlet/remotepageview for this purpose (currently 403 returns to properly jwt-signed server to server request).

Request code is looks like:

ac.url("/plugins/servlet/remotepageview?pageId=196615").get().whenCompleteAsync(
                (resp,ex) -> {
                    System.out.println(resp.getStatus());
                    System.out.println(resp.getStatusText());
                    System.out.println(resp.getBody());
                }, httpExecutionContext.current());

We have already explored other available options (which are already whitelisted) to get Confluence Cloud page rendered outside like /rpc/json-rpc/confluenceservice-v2/renderContent and /wiki/rest/api/content/1234?expand=body.styled_view but results are not acceptable for our purposes. These resources doesn't provide custom macro rendering.
 

Expected Results

Get the exact details being returned by /plugins/servlet/remotepageview.

Actual Results

The http response data are as follows:
Status code: 403
Status text: Forbidden
Response body (full page html omitted): <h1>HTTP Status 403 - Request not in an authorized API scope</h1>

At this stage, this issue is blocker for our Confluence Cloud add-on development (we are porting our server add-on to cloud).