Examine source code of Undertale Loooong Bridge

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Undertale Loooong Bridge",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat-x"
      ]
    },
    "colors": {
      "toolbar": "rgba(133, 86, 180, 0.15)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(135, 153, 234)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(59, 69, 113, 0.35)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(101, 115, 163)",
      "popup": "rgb(59, 69, 113)",
      "popup_text": "rgb(202, 202, 255)",
      "button_background_active": "rgb(140, 87, 37)",
      "button_background_hover": "rgba(189, 146, 105, 0.83)",
      "frame_inactive": "rgb(212, 0, 212)",
      "icons_attention": "rgb(255, 194, 51)",
      "icons": "rgb(254, 244, 255)",
      "ntp_background": "rgb(71, 78, 108)",
      "popup_highlight": "rgb(189, 146, 105)",
      "tab_background_separator": "rgba(255, 255, 255, 0)",
      "tab_selected": "rgba(47, 60, 97, 0.78)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_field_border_focus": "rgb(255, 227, 255)",
      "toolbar_field_border": "rgba(255, 255, 255, 0.54)",
      "toolbar_field_highlight_text": "rgb(255, 255, 255)",
      "toolbar_field_highlight": "rgb(85, 101, 135)",
      "toolbar_vertical_separator": "rgb(195, 9, 195)",
      "tab_loading": "rgb(101, 115, 163)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0a95fb4b-1db5-45ca-a681-598274ff41a3}"
    }
  }
}