You may notice that next to your products in the cart there is a "_uw:" followed by a number. This happens on themes that do not hide hidden line item properties by default.
This is nothing to worry about. It is metadata that we attach to each product in the cart. This is how we track your funnel's conversion metrics which we display back to you within the app. However, if you'd like to make sure the upsell line item properties are hidden we have written a guide (linked below).
Hiding hidden line item properties manually if your theme doesn't support it out of the box.
If you'd like to make sure tracking properties are not displayed to customers you can make a change to your theme to prevent this.
Please let us know if you have any questions. We're happy to help!
The Upsell Wizard Team