Examine source code of Engineering Blueprint

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Engineering Blueprint",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-005-f5f3cf677b1f132c75ddc7bd319dd1fc.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(36, 129, 183)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(39, 136, 193)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(128, 167, 190)",
      "toolbar_field_text": "rgb(73, 73, 88)",
      "tab_line": "rgb(0, 0, 0)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(92, 97, 212)",
      "tab_loading": "rgb(0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{46873167-398d-409a-bc90-9a97e93f39db}"
    }
  }
}