If the Accept-Language header in the incoming request is not "English", then errors returned by the Apps Script API include this message. It contains the same error text translated to the requested locale.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-10-31 UTC."],[[["\u003cp\u003eThe \u003ccode\u003eAccept-Language\u003c/code\u003e header in the request determines the language of error messages.\u003c/p\u003e\n"],["\u003cp\u003eError responses may contain a localized message object with the locale and translated message.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003elocale\u003c/code\u003e field follows the BCP 47 specification for language tags (e.g., "en-US").\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003emessage\u003c/code\u003e field provides the error message translated into the specified locale.\u003c/p\u003e\n"]]],[],null,["# LocalizedMessage\n\n- [JSON representation](#SCHEMA_REPRESENTATION)\n\nIf the `Accept-Language` header in the incoming request is not \"English\", then errors returned by the Apps Script API include this message. It contains the same error text translated to the requested locale.\n\n| JSON representation |\n|-------------------------------------------------|\n| ``` { \"locale\": string, \"message\": string } ``` |\n\n| Fields ||\n|-----------|---------------------------------------------------------------------------------------------------------------------------------------------------------|\n| `locale` | `string` The locale used following the specification defined at \u003chttps://www.rfc-editor.org/rfc/bcp/bcp47.txt\u003e. Examples are: \"en-US\", \"fr-CH\", \"es-MX\" |\n| `message` | `string` The localized error message in the above locale. |"]]