Examine source code of Color-Crosses

{
  "name": "Color-Crosses",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "color-x.png"
    },
    "colors": {
      "frame": "rgba(89, 132, 230, 0)",
      "tab_background_text": "rgba(255, 255, 255, 1)",
      "toolbar": "rgba(23, 76, 122, 0.72)",
      "bookmark_text": "rgba(255, 255, 255, 1)",
      "toolbar_field": "rgba(227, 43, 178, 0.58)",
      "toolbar_field_text": "rgba(255, 255, 255, 1)",
      "tab_line": "rgba(3, 3, 3, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c401524b-5a2a-4367-b537-ff03f2126b55}"
    }
  }
}