Thanks for the explanation – this was my fault. The link I shared above points to the nightly build extracted from our master branch, which includes more features than what will be released with version 5.9. I can confirm that this particular change is targeted for 5.10. I’ve also seen discussions about it in the team channels, so I’m confident it won’t be released in its current form.
We’ll be discussing with the team how to provide a proper release candidate (not a nightly build) when sending out those messages. We’ll also talk about how to accelerate the version number transition from 5.9 to 5.10 in our nightly builds.