Examine source code of Plastic (unofficial)

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Plastic (unofficial)",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(33, 37, 43)",
      "toolbar_text": "rgb(198, 204, 215)",
      "frame": "rgb(24, 26, 31)",
      "tab_background_text": "rgb(95, 102, 114)",
      "toolbar_field": "rgb(24, 26, 31)",
      "toolbar_field_text": "rgb(198, 204, 215)",
      "tab_line": "rgba(169, 178, 195, 0.1)",
      "popup": "rgb(33, 37, 43)",
      "popup_text": "rgb(198, 204, 215)",
      "icons": "rgb(169, 178, 195)",
      "popup_border": "rgb(13, 17, 23)",
      "sidebar_border": "rgb(13, 17, 23)",
      "toolbar_field_border_focus": "rgb(13, 17, 23)",
      "toolbar_field_border": "rgb(13, 17, 23)",
      "tab_loading": "rgba(169, 178, 195, 0.1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{81aae2c2-3f3a-49a3-9093-65d4f28ef9e9}"
    }
  }
}