Examine source code of Nebula stars

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Nebula stars",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 19, 68, 0.5)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(19, 44, 100)",
      "tab_background_text": "rgb(255, 241, 199)",
      "toolbar_field": "rgba(255, 235, 224, 0.75)",
      "toolbar_field_text": "rgb(19, 44, 100)",
      "tab_line": "rgb(198, 188, 255)",
      "popup": "rgb(199, 215, 255)",
      "popup_text": "rgb(133, 52, 0)",
      "tab_loading": "rgb(198, 188, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{15007f32-b875-4fa1-9971-e8a794a967db}"
    }
  }
}