Get Report ID of RDL Report that is embedded inside PowerBI report (Paginated report inside PowerBI)

Hi All.

How Do we get the ReportID of a Paginated Report from a Power BI Report ID?

Explanation:

With the new(ish) PowerBI RDL/Paginated report visual, you can embed a power bi paginated report inside a PowerBI report.

Now, in NOVEMBER 2021 - we can use this feature in App Owns Data/Customer Owns Data mode of embedding.

https://powerbi.microsoft.com/en-gb/blog/power-bi-november-2021-feature-summary/#post-17912-_Toc87473967 (

(Support embedding a Power BI report that contains a paginated report visual)

Great... except. we need to know the ReportID of the RDL Report, but, as a software application, we only have the POWER BI Report ID.

Existing GetReport API Doesn't give the 'linked RDL Reports' https://docs.microsoft.com/en-us/rest/api/power-bi/reports/get-report 

{
  "datasetId": "cfafbeb1-8037-4d0c-896e-a46fb27ff229",
  "id": "5b218778-e7a5-4d73-8187-f10824047715",
  "name": "SalesMarketing",
  "webUrl": "https://app.powerbi.com//reports/5b218778-e7a5-4d73-8187-f10824047715",
  "embedUrl": "https://app.powerbi.com/reportEmbed?reportId=5b218778-e7a5-4d73-8187-f10824047715"
}

So, Where/How Do we get the ID of an RDL file from a Report?

Please help.

One option is to get all the RDL reports in the whole workspace that the Power BI Report resides, but in our app, we only give people very specific access, not whole workspaces, so this doesn't hold for security reasons.