CMS Blocks are the best option to add CMS content above products on a specific category page via the Admin Panel. CMS Blocks are reusable pieces of content that can be inserted into any page or layout using widgets or layout XML. CMS Blocks can be assigned to specific categories using the Display Settings tab in the category edit page. The developer can choose the Display Mode for the category, which determines how the CMS Block and the products are displayed on the category page. For example, the developer can choose Static block and products to show both the CMS Block and the products, or Static block only to show only the CMS Block and no products. Reference:Adobe Commerce Developer Documentation,Adobe Inc.

To customize the header of email templates, the developer needs to place the new template in the /Magento_Email/email/header.html path of the theme. This will override the default header template from the Magento_Email module. The /Magento_Email/templates/override/html/header.html path is not valid and will not work. The /Magento_Theme/html/header.html path is used for customizing the header of web pages, not emails. Reference: [Customize email templates], [Email templates overview]

To add text to an email template that supports translations, the developer should use the {{trans}} directive with the text enclosed in double quotes. For example:

{{trans ''Lorem Ipsum is simply dummy text of the printing''}}

This will render the text as it is, or translate it if a translation file is available for the current locale. If the text contains a variable, the developer should use a placeholder with a percent sign and pass the variable name as an argument. For example:

{{trans ''%items items'' items=''numItems''}}

This will render the text with the value of numItems replacing the %items placeholder, or translate it if a translation file is available for the current locale. The {{translations}} directive is not valid and will not work. Reference: [Translate email templates], [Email template syntax]

The theme.xml file is responsible for specifying the parent theme of a custom theme. The file should contain the element with the value of the parent theme's directory, such as MagentoMuma. The view.xml file is used to configure the theme's images, fonts, and layout. The registration.php file is used to register the theme in the system. Reference: [Create a theme], [theme.xml]

To register a new page layout in a custom theme, the developer needs to create a layouts.xml file in the app/design/frontend/<VendorName>/<ThemeName>/Magento_Theme/layout directory. The layouts.xml file should contain the <layout> element with the id, label, and file attributes. The id attribute is used to reference the layout in other layout files, the label attribute is used to display the layout name in the admin panel, and the file attribute is used to specify the path to the layout file relative to the web directory of the theme. The app/design/frontend/<VendorName>/<ThemeName>/layouts.xml and app/design/frontend/<VendorName>/<ThemeName>/Magento_Theme/layouts.xml files are not valid and will not work. Reference: [Create a new page layout], [layouts.xml]