Examine source code of Kanagawa

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Kanagawa ",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(42, 42, 55)",
      "toolbar_text": "rgb(220, 215, 186)",
      "frame": "rgb(22, 22, 29)",
      "tab_background_text": "rgb(200, 192, 147)",
      "toolbar_field": "rgb(22, 22, 29)",
      "toolbar_field_text": "rgb(200, 192, 147)",
      "tab_line": "rgb(163, 212, 213)",
      "popup": "rgb(31, 31, 40)",
      "popup_text": "rgb(220, 215, 186)",
      "tab_loading": "rgb(163, 212, 213)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{90d1f3aa-5b7d-4f20-a136-9ad1afe7b2da}"
    }
  }
}