The Test Wikipedia instance of Section Translation was updated to be used on both desktop and mobile as a way to try the unified dashboard.
Since Section Translation is available in a specific set of languages, the test instance was enabled for those. This is problematic since now the test instance cannot be used for desktop on languages for which Content Translation is supported on desktop. For example, going to the desktop version of Test Wikipedia it is not possible to start a translation from English to Japanese.
This ticket proposes to support all languages in test wikipedia for users speaking any language to try how the unified dashboard will work for them.