Examine source code of mhitheme

{
  "name": "mhi banner",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "mhi banner.png"
    },
    "colors": {
      "frame": "rgba(28, 22, 19, 1)",
      "tab_background_text": "rgba(250, 247, 245, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{929b6bf0-db26-4bd0-b329-7107d26d7219}"
    }
  }
}