Setting blocks in a menu item for a menu block

If a menu item under your menu block is supposed to open one or more blocks, the menu item's type should be block and you should send the list of blocks' slug inside it. For example: ‍‍‍

{
    "items": [
        {
            "type": "block",
            "title": "Show list of blocks",
            "blocks": [
                "block_1_slug",
                "block_2_slug",
                "block_3_slug,
            ]
        }
    ]
}

The response contains the basic data for each block.