Examine source code of Green background

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Green background",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-037-b73f9b34467ba541de861f5b4c0c6316.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(255, 255, 255, 0.62)",
      "toolbar_text": "rgb(108, 108, 108)",
      "frame": "rgb(64, 173, 51)",
      "tab_background_text": "rgb(232, 232, 232)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgba(21, 78, 23, 0.38)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(0, 0, 0)",
      "button_background_active": "rgb(255, 255, 255)",
      "tab_loading": "rgba(21, 78, 23, 0.38)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{31d408f8-ba7b-4100-858a-903d191dbb66}"
    }
  }
}