App Store developer id, e.g. `284882218` for Meta Platforms. It is the `developer.id` on every app.

Two-letter storefront code, e.g. `us`, `gb` or `jp`, case-insensitive. Prices, ratings, reviews and text are specific to it. A code Apple does not run a store for is refused. Default: `us`.

Language of the text, as `ll-cc`, e.g. `es-mx` or `ja-jp`. Changes the language of descriptions and price labels inside the storefront. Default: the storefront's own language.