Google Ads updated its About product category insights help document to say that it "automatically assigns your products to categories using a continuously evolving product taxonomy." This was previously not documented on the Google Ads side but has been on the Google Merchant Center side for several years.
Google added this new section to that Google Ads help document:
How products are assigned to categories:Google automatically assigns your products to categories using a continuously evolving product taxonomy. This ensures that your products appear in the most relevant search results for potential customers. Learn more about Google Product Category.
If you think that a product has been misclassified, you can manually override the categorization by using the google_product_category attribute in your Merchant Center feed. Submitting this attribute tells Google to prioritize your specific classification over the automated categorization.
So I don't think this is a change in how Google handles product categorization but a clarification to the Google Ads help documentation to be more in sync with how it has worked since at least 2019.
Google actually made a ton of changes to this document, mostly to just clean it up. I don't see any substantial changes otherwise - here is a screenshot of the before/after text changes:
Google also made similar updates to these two related help documents:
Forum discussion at X.
