This section explains that;
My suggestion would be that if you don’t provide (as a part of the default Flowable Web UI builds) an ‘en-US.json’ (or a ‘en-GB.json’, etc.) then, by default, you should map ‘en-US’ to ‘en’.
That way users won’t receive a error message in their browser console.
I understand that for your specific case that would be preferable.
But there are of course numerous other possibilities. That’s why we’ve chosen the default fallback to the en.json file.
And provide the instructions to configure it differently.
Hope this works for you.
I don’t really have a specific use case
I’m just learning about Flowable by playing around with the all-in-one Docker image (6.4.1) and using the UI Apps and the REST API.
I just happened to notice the error message in the console and thought that maybe the ‘en-US.json’ was not included in the latest build for some reason…