Examine source code of Rhythmical (Dark)

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "210625",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0.54)",
      "toolbar_text": "rgb(225, 225, 225)",
      "frame": "rgb(142, 179, 201)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(70, 70, 70, 0.82)",
      "toolbar_field_text": "rgb(225, 225, 225)",
      "tab_line": "rgba(72, 219, 160, 0.44)",
      "popup": "rgb(74, 74, 74)",
      "popup_text": "rgb(225, 225, 225)",
      "button_background_active": "rgba(129, 247, 234, 0.32)",
      "button_background_hover": "rgba(202, 129, 247, 0.32)",
      "icons_attention": "rgba(16, 255, 236, 0.85)",
      "ntp_text": "rgba(225, 225, 225, 0.85)",
      "popup_border": "rgba(225, 225, 225, 0)",
      "sidebar_border": "rgba(225, 225, 225, 0)",
      "sidebar_highlight_text": "rgb(247, 247, 247)",
      "sidebar_highlight": "rgba(143, 61, 208, 0.85)",
      "sidebar_text": "rgb(242, 242, 242)",
      "sidebar": "rgb(74, 74, 74)",
      "tab_loading": "rgba(92, 172, 161, 0.81)",
      "tab_selected": "rgba(122, 75, 158, 0.34)",
      "tab_text": "rgb(230, 230, 230)",
      "toolbar_bottom_separator": "rgba(25, 25, 25, 0.81)",
      "toolbar_field_border_focus": "rgba(162, 85, 225, 0)",
      "toolbar_field_border": "rgb(96, 96, 96)",
      "toolbar_field_focus": "rgb(78, 78, 78)",
      "toolbar_field_highlight_text": "rgb(255, 255, 255)",
      "toolbar_field_highlight": "rgba(143, 61, 208, 0.85)",
      "toolbar_field_text_focus": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{173908db-ebc9-485c-8921-ad89f116885e}"
    }
  }
}