Examine source code of Event Horizon

{
  "manifest_version": 2,
  "name": "Event Horizon",
  "version": "1.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "event-horizon-theme@thelastbobreek"
    }
  },
  "theme": {
    "colors": {
      "frame": "#08080f",
      "frame_inactive": "#08080f",
      "tab_background_text": "#a04828",
      "tab_line": "#e06640",
      "toolbar": "#08080f",
      "toolbar_text": "#f07248",
      "bookmark_text": "#f07248",
      "toolbar_field": "#06060a",
      "toolbar_field_text": "#f07248",
      "toolbar_field_border": "#2a2a35",
      "toolbar_field_focus": "#0e0e18",
      "toolbar_field_text_focus": "#f07248",
      "toolbar_field_border_focus": "#e06640",
      "icons": "#e06640",
      "icons_attention": "#f07248",
      "button_background_hover": "#14141e",
      "button_background_active": "#1a1a26",
      "popup": "#0d0d14",
      "popup_text": "#e06640",
      "popup_border": "#2a2a35",
      "popup_highlight": "#1a1a26",
      "popup_highlight_text": "#f07248",
      "sidebar": "#06060a",
      "sidebar_text": "#e06640",
      "sidebar_highlight": "#1a1a26",
      "sidebar_highlight_text": "#f07248",
      "sidebar_border": "#2a2a35",
      "ntp_background": "#06060a",
      "ntp_text": "#e06640"
    }
  }
}