This came up in #1470 — there's an inconsistency/ambiguity in how env files are handled across examples.

The current heuristic (as @badmonster0 explained) is: if an example contains XYZ_API_KEY, we provide a .env.example and expect users to copy it over to .env. Otherwise, we just use .env directly. This doesn't seem to be applied consistently; some examples document it:

...others don't.

I'm thinking we either standardize on .env.example everywhere (with clear comments like the above ^) or document a consistent pattern in a central place.