The issue has been fixed. The database Data.StackExchangePOC is gone and cross-site queries are working fine without having to use rene's workaround.

While we wait for this rogue database to be dropped, hopefully accompanied with an answer explaining what Proof of Concept we can look forward for, let's fix our network-wide queries by checking if we have access to the database we like to include. We can use has_dbaccess([database name]) which r...

Sorry, this was me, and it is now fixed. Before going on vacation this past weekend, I had started work on a mini-project to enable developers to test Data Explorer locally. To be portable, we can't require developers to restore 300+ databases, especially those the size of Stack Overflow. This me...