Temp Project Backup Location

When restoring a gateway backup, where does it place the temporary backup of the projects dir during the restore process if "Disable Temp Project Backup" is not checked?

I couldn't find anything on the documentation page:
https://docs.inductiveautomation.com/display/DOC81/Gateway+Backup+and+Restore

I thought it might go to the "Backup Folder" config from "Gateway Settings", but nothing appeared there.

Thoughts?
-Shane

Projects will be temporarily copied to $ignitionInstallDirectory/data/__projects_$timestamp.bak/.

How temporarily? Does it only hang around until the restore is complete?

I've done a couple test restores and never saw anything created...