Basically, it's to add a flag to local build so that it always uses newest timestamp to help make things easier for QE testing of PRs. There are a couple of workflows where the PR build site will fail to install on a newer JBT, and a locally built site of that repo will fail in the same way.
Since testing PRs before pushing to master is now standard operating procedure, making sure the workflow actually works is important, so any feedback before or after will be appreciated.