Examine source code of Nature-Calmness

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Nature-Calmness",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(73, 82, 89)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(142, 179, 201)",
      "tab_background_text": "rgb(248, 248, 248)",
      "toolbar_field": "rgb(221, 230, 230)",
      "toolbar_field_text": "rgb(10, 10, 11)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(52, 52, 53)",
      "popup_text": "rgb(230, 230, 234)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  }
}