Working with B2C service for user creation and authentication with custom policy method. On the b2c Signup page, there is a usecase to add a drop-down list to populate a dynamic list of countries to the user. Are there any helpful references for modifying the b2c custom policy localization and HTML to handle this dropdown scenario and sync with the custom policy?
The sample pointed by @rbrayb is a good starting point. Basically, you will retrieve the dynamic list of countries using Vanilla JS from within your HTML template.
The locale code being used by your policy will be passed in the ui_locales query param.