Examine source code of Display Pick New Tab

{
  "name": "Display Pick Theme",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "wallpaperflare.com_wallpaper (2).jpg"
    },
    "colors": {
      "frame": "rgba(255, 255, 255, 1)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(54, 168, 209, 1)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(56, 126, 224, 0.84)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{27338dd0-3413-41c7-ac8c-c1c4700c8280}"
    }
  }
}