Examine source code of Red line

{
  "manifest_version": 2,
  "version": "1.1.0",
  "name": "Red line",
  "theme": {
    "colors": {
      "bookmark_text": "white",
      "button_background_active": "rgba(255, 0, 0, 0.40)",
      "button_background_hover": "#000000",
      "icons": "white",
      "icons_attention": "#6db8f2",
      "frame": "#121212",
      "frame_inactive": "#1f1f1f",
      "ntp_background": "#202020",
      "ntp_text": "white",
      "popup": "rgba(18, 18, 18, 0.64)",
      "popup_border": "rgba(255, 53, 0, 0.16)",
      "popup_text": "#ffffff",
      "popup_highlight": "rgba(255, 0, 0, 0.5)",
      "popup_highlight_text": "white",
      "sidebar": "#121212",
      "sidebar_border": "rgba(255, 53, 0, 0.16)",
      "sidebar_highlight": "rgba(255, 53, 0, 0.84)",
      "sidebar_highlight_text": "white",
      "sidebar_text": "white",
      "tab_background_text": "white",
      "tab_background_separator": "#1f1f1f",
      "tab_line": "#ff3500",
      "tab_loading": "rgba(255, 0, 0, 1)",
      "tab_text": "white",
      "toolbar": "#353535",
      "toolbar_bottom_separator": "rgba(255, 53, 0, 0.18)",
      "toolbar_field": "rgba(18, 18, 18, 0.32)",
      "toolbar_field_border": "rgba(255, 53, 0, 0.16)",
      "toolbar_field_separator": "rgba(255, 53, 0, 0.16)",
      "toolbar_top_separator": "rgba(255, 0, 0, 0.5)",
      "toolbar_field_text": "white",
      "toolbar_vertical_separator": "rgba(255, 53, 0, 0.16)"
    }
  }
}