This is a good feature if you want to show a specific extra image or text, on products in a certain product category.
First step to this is a make a product layout in the Divi theme builder. After this its possible to use the condition feature on the module you only want to show on the specific category.
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Afther click on advanced -> click add display conditions.
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Then you select post category.
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Then select is and the post category where the module need to show.
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After this you save the setting and save the theme builder layout. Then the module will only show on the specific category.