Magento 2 - Passing argument from backoffice in Category Layout Update XML field to frontend module or phtml

Question

In Magento 1 I sometimes used this way to pass an argument to a category, directly from the back office

Category > Custom Design tab > XML Design Update

<reference name="product_list">
    <action method="setData"><key>giftCardId</key><value>955</value></action>
</reference>

Could you tell me what will be the equivalent syntax in Magento 2, Using the same way:

Category > Design > Layout Update XML

The main idea is to pass a value for a specific category, that could be retrieved in a custom module in frontend.

Edit: I know that I can add a custom category attribute to do that too, but the point is really, does an equivalent syntax exists.

Answer 1

You can pass arguments in M2

https://devdocs.magento.com/guides/v2.3/frontend-dev-guide/layouts/xml-instructions.html#argument

Example:

Setting a value of css_class in the [app/code/Magento/Theme/view/frontend/layout/default.xml] layout file:

<arguments>
    <argument name="css_class" xsi:type="string">header links</argument>
</arguments>

Using the value of css_class in [app/code/Magento/Theme/view/frontend/templates/html/title.phtml]:

$cssClass = $this->hasCssClass()