Hi Evan,
The Developer Toolkit app is no longer available. This was communicated to subscribed customers via a proactive ticket that stated:
The following GoodData Labs application - “Accelerator Toolkit” has been deprecated and will be deleted from GoodData Labs on May 5, 2022, without a replacement option.
ACTION REQUIRED!
Switch from the GoodData Labs application that you are using to an alternative method of completing the task.