The data-mage-init HTML attribute is used to initialize the jQuery UI widget for a specific HTML tag.
This attribute specifies the name of the widget and its configuration options as a JSON object.
The x-magento-init HTML attribute is used to initialize RequireJS modules for a specific HTML tag.
The data-ui HTML attribute does not exist in Adobe Commerce.
Verified Reference: [Adobe Commerce Developer Guide - Initialize JavaScript components using the
data-mage-init attribute]
To initialize the jQuery UI widget in Adobe Commerce, the data-mage-init attribute is used in the
HTML tag. This attribute allows specifying the widget's component and its configuration in a JSON
format. The x-magento-init is used for initializing JavaScript components in a similar manner but is
typically used within <script> tags. There's no standard data-ui attribute used for this purpose in
Magento 2.