Examine source code of YouTube 2021

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "YouTube 2021",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-037-b73f9b34467ba541de861f5b4c0c6316.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(231, 0, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(147, 0, 0)",
      "tab_background_text": "rgb(77, 0, 0)",
      "toolbar_field": "rgb(182, 0, 0)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(147, 0, 0)",
      "popup": "rgb(147, 0, 0)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgba(77, 0, 0, 0.48)",
      "button_background_hover": "rgba(77, 0, 0, 0.23)",
      "icons": "rgb(102, 0, 0)",
      "ntp_background": "rgb(147, 0, 0)",
      "ntp_text": "rgb(0, 0, 0)",
      "sidebar_text": "rgb(255, 255, 255)",
      "sidebar": "rgb(231, 0, 0)",
      "tab_selected": "rgb(189, 0, 0)",
      "tab_loading": "rgb(147, 0, 0)"
    }
  }
}