Hi, that was me. Sorry for the delay, someone tagged me on discord about this but I forgot to reply here.

The ability to view this that far out was as simple as forcing the web browser to report the wrong date / time and being able to pull the information directly from the publicly accessible UA site (nothing special, no API access, et cetera). There was a time period where you could even do out to December by using the same method.

Was the ability to access this removed because it being posted (not just by me) to multiple spots like FT, reddit, or even select FB groups? Unlikely. This feels more like an unintended "fix" due to some of the recent backend updates that the DT group have been completed. It has been known about for a long time and while certain other items have been broken recently, it may have been patched in part of an attempt to fix those other broken items by changing over the date check to server side or is related to some expiring SSL certs with the multiple systems throwing an error as they see a mismatch (I have not checked into this one yet to confirm, but we know if that is the cause in ~14 days.

In my personal view, while the UA DT group is generally great (yes, I know all about the other issues like seat-gate, et alii), it just seems odd that they would focus time on resolving this specific issue right away, unless it had been planned for a long time (we all know how UA moves at times) or was a side effect of another patch.
​They generally are more focused on keeping things running and stopping the unauthorized scraping and reselling of PN/PZ data that is currently occurring.