While MultiSiteFiltering is enabled, it is currently not possible to query content that is under the "For All Sites"-folder.
In my example I have a page with a ContentArea. Into that ContentArea I've added a Block that was created to be available for all sites. When using the expand parameter while querying the Page, I get the blocks' name correctly. But when querying the blocks' content reference directly I get "Content not found".
After some digging around I concluded that this is due to the code that is run in ContentApiSiteFilter.ShouldFilterContent().
I've solved it locally in a way that fits my use case, but it would be nice if it's a general possibility with the API.
Is this working as intended or is it something that is intended to be possible to do while having MultiSiteFiltering enabled? Maybe I missed something? :)