[Web Install] How do related applications impact these APIs?

[mhochk]

The explainer calls out

When the related_applications and prefer_related_applications key/values are present in the manifest, the UA should try to handoff the install to the prefered catalog.

What should be the return value of install() in this case? And should future calls to getInstalledApps be expected to include information about this app?

My assumption would be that it is expected to behave like any other case, returning the manifest_id and appropriately including the manifest_id in future getInstalledApps calls, but it would be good to confirm.