Examine source code of Charcoal black v2

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Charcoal black",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(36, 36, 36)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(247, 247, 247)",
      "toolbar_field": "rgb(70, 70, 70)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgba(255, 0, 0, 0)",
      "popup": "rgb(36, 36, 36)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(0, 0, 0)",
      "button_background_hover": "rgb(0, 0, 0)",
      "frame_inactive": "rgb(0, 0, 0)",
      "icons_attention": "rgb(72, 72, 72)",
      "ntp_background": "rgb(0, 0, 0)",
      "popup_border": "rgba(72, 72, 72, 0)",
      "tab_selected": "rgb(70, 70, 70)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_bottom_separator": "rgba(255, 255, 255, 0)",
      "toolbar_field_border": "rgba(0, 0, 0, 0)",
      "toolbar_field_highlight_text": "rgb(174, 255, 254)",
      "toolbar_field_highlight": "rgba(0, 0, 0, 0)",
      "toolbar_top_separator": "rgba(72, 72, 72, 0)",
      "tab_loading": "rgba(255, 0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c3ef3c0d-906b-41a0-9de5-e81826da829f}"
    }
  }
}