Examine source code of Strawberry time

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Strawberry season",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(254, 206, 202, 0.5)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(254, 206, 202)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(0, 96, 34)",
      "tab_line": "rgb(255, 0, 0)",
      "popup": "rgb(255, 241, 235)",
      "popup_text": "rgb(0, 96, 34)",
      "ntp_background": "rgb(255, 241, 235)",
      "ntp_text": "rgb(255, 0, 0)",
      "toolbar_field_border": "rgb(255, 250, 0)",
      "tab_loading": "rgb(255, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7019f561-70a2-4d77-8528-737de915c415}"
    }
  }
}