v1.0 metadata for functions returning a stream look incorrect

The type graph.report looks like this:

<ComplexType Name="report">
    <Property Name="content" Type="Edm.Stream"/>
</ComplexType>

The report type is returned by a number of functions, for example:

<Function Name="getMailboxUsageDetail" IsBound="true" IsComposable="true">
    <Parameter Name="bindingParameter" Type="graph.reportRoot"/>
    <Parameter Name="period" Type="Edm.String" Nullable="false" Unicode="false"/>
    <ReturnType Type="graph.report" Nullable="false"/>
</Function>

What this suggests to me is that the url to return the report (a CSV file to be read as a stream) above would look like this:

https://graph.microsoft.com/v1.0/reports/getMailboxUsageDetail(period%3D'D7')/content

but in fact the url to return the report is:

https://graph.microsoft.com/v1.0/reports/getMailboxUsageDetail(period%3D'D7')

I couldn't spot anything in the OData 4.01 specifications supporting this strange wrapping of the Stream type (with special behaviour to ignore the content property name). Why isn't the ReturnType for all these functions just Edm.Stream?

AB#7460

The issue names no repository files, tests, or entry points. Start by comparing the shown graph.report and getMailboxUsageDetail metadata with the OData 4.01 stream-return rules; done means determining whether the metadata or URL behavior is inconsistent and documenting the standards-based explanation.