CartoDB/cartodb20

{
  "type": "object",
  "additionalProperties": false,
  "anyOf": [
    { "required": ["categories"] },
    { "required": ["html"] }
  ],
  "properties": {
    "categories": {
      "type": "array",
      "required": [
        "title"
      ],
      "additionalProperties": false,
      "items": {
        "type": "object",
        "required": [
          "title"
        ],
        "additionalProperties": false,
        "properties": {
          "title": {
            "type": "string"
          },
          "color": {
            "type": "string",
            "pattern": "^#(?:[0-9a-fA-F]{3}){1,2}$"
          },
          "icon": {
            "type": "string"
          }
        }
      }
    },
    "html": { "type": "string" }
  }
}