Examine source code of FF Colour purple theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Purple",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-027-1049af643fc55b4ffd4a8575444547c5.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(86, 41, 125)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(64, 28, 94)",
      "tab_background_text": "rgb(200, 200, 200)",
      "toolbar_field": "rgb(64, 28, 94)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(64, 28, 94)",
      "popup_text": "rgb(255, 255, 255)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{edeb1fb0-0cbd-4e0e-a70f-90416e773a12}"
    }
  }
}