Examine source code of Space dark Background

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Space Background",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(243, 244, 247)",
      "toolbar_text": "rgb(5, 5, 5)",
      "frame": "rgb(255, 255, 255)",
      "tab_background_text": "rgb(247, 247, 247)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(9, 9, 9)",
      "tab_line": "rgb(8, 8, 8)",
      "popup": "rgb(243, 244, 247)",
      "popup_text": "rgb(9, 9, 9)",
      "tab_loading": "rgb(8, 8, 8)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7aa65668-0c55-4fea-a611-90b0e2c49a9b}"
    }
  }
}