Examine source code of Dark Rainbow

{
  "name": "Dark Rainbow",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "dark_pastel.png"
    },
    "colors": {
      "frame": "#19c9e8",
      "tab_background_text": "rgba(37, 24, 31, 1)",
      "bookmark_text": "rgba(37, 24, 31, 1)",
      "toolbar_field_text": "rgba(37, 24, 31, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a6262eca-9747-4849-a310-768afa498039}"
    }
  }
}