Translations:New Template System in LS3.x/93/en

If you read the frontend rendering code, you'll see that those files names appear directly in it. That's why they are mandatory. Eg: https://github.com/LimeSurvey/LimeSurvey/blob/2398dda3b425da1a37d4611cd7963d39ac739987/application/helpers/SurveyRuntimeHelper.php#L462