Examine source code of squares grey

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "squares grey",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(17, 29, 243, 0)",
      "toolbar_text": "rgb(231, 204, 20)",
      "frame": "rgb(124, 120, 127)",
      "tab_background_text": "rgb(211, 211, 201)",
      "toolbar_field": "rgba(7, 52, 245, 0.01)",
      "toolbar_field_text": "rgb(166, 166, 175)",
      "tab_line": "rgb(232, 16, 16)",
      "popup": "rgb(245, 245, 241)",
      "popup_text": "rgb(178, 172, 180)",
      "tab_loading": "rgb(232, 16, 16)"
    }
  }
}