Examine source code of MySimpleRedDark

{
  "name": "MySimpleRedDark",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "RedDark.png"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(153, 153, 153, 1)",
      "toolbar": "rgba(46, 46, 46, 1)",
      "bookmark_text": "rgba(112, 112, 112, 1)",
      "toolbar_field": "rgba(138, 138, 138, 1)",
      "toolbar_field_text": "rgba(0, 0, 0, 1)",
      "tab_line": "rgba(148, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b5e1b0e1-a40b-42f3-b1e0-2e6532089309}"
    }
  }
}