A block is a designed HTML element of your email, for example a story, a header, a footer, etc. Blocks are stored in a template's Block Library, and, when in the Editor's Layout Mode, can be dropped into the Sections of your email to achieve different layouts without requiring a new template.
In HTML terms, a block is nearly always an HTML table.
The following code should be nested inside opening and closing section markers. For completeness, we have added a slot marker too.
|Name||No||Text||Displayed in the Block Library to help users identify the block.|
|Width||No||Number||If used, this block will only be shown by default if its Width (declared in pixels with no units) is equal to or less than than a section's Width property. Users can still use this block if they adjust the Block Library's filtering options. This property is useful to prevent users from using blocks that are too wide for sections and could break a template's layout.|
|LibraryOnly||No||True/False||Blocks which have this property to set to true will be added to the template's block library but not shown in the default layout. This is useful when you create a template with many blocks to save users needing to delete unneeded ones each time they create a new email.|