Used for: setting the category of the export channel for your item.
The "set category" rule acts as an alternative for the "categories" step that each export channel has. Usually the categories step is the easiest to use for setting the export channel's category for your items, however there are some cases in which rules get the job done faster and/or better.
For example, your shop might be specialized in one specific type of item, that all fall under one category of the export channel. In this case you want to set the category of all your items to the same category, which is easier done in rules. Also, some channels require you to divide your items into e.g. female clothes and male clothes. In this case you would need rules to check the gender and to check what type of clothing item a product is.
We'll show both examples in the screenshots below. The first screenshot shows how you set the category for all items in your feed.
The screenshot below is an example of how you would also take gender into account when setting the category for your items.