The Teaser text is a short, free text per product (e.g. "New", "Organic", "Limited") that you can show in the product box above or below the product name.
You maintain the text per product via a custom field. It is displayed as soon as you set a product box "Slot" to "Teaser text".
Configuration
Theme configuration
Switch to the "Listing pages" tab
Open the "Product box" block
Set "Slot above the product name" or "Slot below the product name" to "Teaser text (custom field)"
Save your changes after editing
You maintain the text per product via the "Teaser text" custom field.
Tab "Listing pages" => Block "Product box" => Section "Content" => Slot above/below the product name
"Teaser text" (Products)
You can find more information about the "Teaser text" custom field here: