str ID of the promotion. For example, "free gift".
The value must be a UTF-8 encoded string with a length limit
of 128 characters, and match the pattern:
``a-zA-Z][a-zA-Z0-9_]*``. For example, id0LikeThis or
ID_1_LIKE_THIS. Otherwise, an INVALID_ARGUMENT error is
returned.
Corresponds to Google Merchant Center propertypromotion_id__.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[],[],null,[]]
