Examine source code of bongo cat dark mode

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "bongo cat dark mode",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(7, 50, 84, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(88, 44, 177, 0)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(255, 255, 255)",
      "icons_attention": "rgba(117, 67, 218, 0.75)",
      "icons": "rgb(255, 255, 255)",
      "tab_selected": "rgb(255, 255, 255)",
      "tab_text": "rgb(0, 0, 0)",
      "toolbar_bottom_separator": "rgba(210, 167, 25, 0)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{d1a59ade-c14b-40f5-a42b-261ef141d181}"
    }
  }
}