Examine source code of Hearts gifts

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Hearts gifts",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(255, 194, 217, 0.5)",
      "toolbar_text": "rgb(137, 0, 75)",
      "frame": "rgb(247, 182, 183)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(121, 0, 153)",
      "tab_line": "rgb(242, 173, 26)",
      "popup": "rgb(255, 221, 221)",
      "popup_text": "rgb(95, 0, 81)",
      "ntp_background": "rgb(255, 221, 221)",
      "ntp_text": "rgb(95, 0, 81)",
      "popup_border": "rgb(242, 173, 26)",
      "toolbar_field_border": "rgb(242, 173, 26)",
      "toolbar_field_focus": "rgb(255, 221, 225)",
      "tab_loading": "rgb(242, 173, 26)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f8d82e4d-5a01-4a1a-9511-c69674cd8def}"
    }
  }
}