env.DEV is not ever true

I created a minimal reproduction at https://stackblitz.com/edit/github-z1kfgi-1gya7x?file=src%2Fdocument.ts that puts a single word on the home page, either "foo" or "bar". It will always be "foo." You can see that in document.ts, if env.DEV is true, it shoould be set to 'bar.' I tried with both npm run dev and npm build && npm preview, it shows as foo in both cases. I'm unsure under what conditions it would *ever* be true if not one of those two use cases.