I want to know the system locale codes on App Automate devices so that I can perform localization, regional functionality, compatibility, and other testing on my app. Where can I get these?

The locale codes that you use to test your app on local devices work on BrowserStack devices, too. You can find locale codes for iOS and Android platforms on the web. For example, see iOS Locale Identifiers for iOS, and Locale Codes for Android.

To test how your app handles localization on BrowserStack devices, see Set Localization Options in BrowserStack documentation.