Per T180015#3835408 deployment on wmf infrastructure will likely require audio files to be going into Swift rather than being stored in a directory (see wikispeech_mockup readme).
Ideally the TTS server should have a configurable file storage backend so that swift could be used if available.
@HannaLindgren, @HaraldBerthelsen and @NikolajLindberg: how much work do you think it would be to use Swift on the server?
Current status: Waiting for input from @Lokal_Profil
This will be implemented in the MediaWIki extension instead. This task will either be updated to reflect that or closed with a pointer to the new task for that
Audio files are now stored by the MediaWiki extension using the normal FileBackend mechanism (allowing for Swift) (T246080)