Examine source code of Transit Time Filter

{
  "manifest_version": 2,
  "name": "Transit Time Filter",
  "description": "See, filter, and sort hotel results by public transit time across major booking sites.",
  "version": "0.4.0",
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "transit-time-filter@transitfilter.app",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "alarms",
    "https://*.booking.com/*",
    "https://www.airbnb.com/*",
    "https://www.airbnb.it/*",
    "https://www.airbnb.co.uk/*",
    "https://www.airbnb.de/*",
    "https://www.airbnb.fr/*",
    "https://www.airbnb.es/*",
    "https://www.trivago.com/*",
    "https://www.trivago.it/*",
    "https://www.trivago.co.uk/*",
    "https://www.trivago.de/*",
    "https://www.trivago.fr/*",
    "https://www.trivago.es/*",
    "https://www.expedia.com/*",
    "https://www.expedia.it/*",
    "https://www.expedia.co.uk/*",
    "https://www.expedia.de/*",
    "https://www.expedia.fr/*",
    "https://www.expedia.es/*",
    "https://*.hotels.com/*",
    "https://*.agoda.com/*",
    "https://*.trip.com/*",
    "https://*.kayak.com/*",
    "https://*.kayak.it/*",
    "https://*.kayak.co.uk/*",
    "https://*.kayak.de/*",
    "https://*.kayak.fr/*",
    "https://*.kayak.es/*",
    "https://*.priceline.com/*",
    "https://api.traveltimeapp.com/*",
    "https://routes.googleapis.com/*",
    "https://api.transitous.org/*",
    "https://nominatim.openstreetmap.org/*",
    "https://www.google-analytics.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.booking.com/searchresults*",
        "*://*.booking.com/hotel/*",
        "*://*.airbnb.com/s/*",
        "*://*.airbnb.it/s/*",
        "*://*.airbnb.co.uk/s/*",
        "*://*.airbnb.de/s/*",
        "*://*.airbnb.fr/s/*",
        "*://*.airbnb.es/s/*",
        "*://*.airbnb.com/rooms/*",
        "*://*.airbnb.it/rooms/*",
        "*://*.airbnb.co.uk/rooms/*",
        "*://*.airbnb.de/rooms/*",
        "*://*.airbnb.fr/rooms/*",
        "*://*.airbnb.es/rooms/*",
        "*://*.trivago.com/*",
        "*://*.trivago.it/*",
        "*://*.trivago.co.uk/*",
        "*://*.trivago.de/*",
        "*://*.trivago.fr/*",
        "*://*.trivago.es/*",
        "*://*.expedia.com/*Hotel-Search*",
        "*://*.expedia.com/*hotel-search*",
        "*://*.expedia.it/*Hotel-Search*",
        "*://*.expedia.it/*hotel-search*",
        "*://*.expedia.co.uk/*Hotel-Search*",
        "*://*.expedia.co.uk/*hotel-search*",
        "*://*.expedia.de/*Hotel-Search*",
        "*://*.expedia.de/*hotel-search*",
        "*://*.expedia.fr/*Hotel-Search*",
        "*://*.expedia.fr/*hotel-search*",
        "*://*.expedia.es/*Hotel-Search*",
        "*://*.expedia.es/*hotel-search*",
        "*://*.expedia.com/*",
        "*://*.expedia.it/*",
        "*://*.expedia.co.uk/*",
        "*://*.expedia.de/*",
        "*://*.expedia.fr/*",
        "*://*.expedia.es/*",
        "*://*.hotels.com/Hotel-Search*",
        "*://*.hotels.com/*",
        "*://*.agoda.com/*",
        "*://*.trip.com/hotels*",
        "*://*.trip.com/hotels/*",
        "*://*.kayak.com/hotels*",
        "*://*.kayak.com/hotels/*",
        "*://*.kayak.com/stays*",
        "*://*.kayak.com/stays/*",
        "*://*.kayak.it/hotels*",
        "*://*.kayak.it/hotels/*",
        "*://*.kayak.it/stays*",
        "*://*.kayak.it/stays/*",
        "*://*.kayak.co.uk/hotels*",
        "*://*.kayak.co.uk/hotels/*",
        "*://*.kayak.co.uk/stays*",
        "*://*.kayak.co.uk/stays/*",
        "*://*.kayak.de/hotels*",
        "*://*.kayak.de/hotels/*",
        "*://*.kayak.de/stays*",
        "*://*.kayak.de/stays/*",
        "*://*.kayak.fr/hotels*",
        "*://*.kayak.fr/hotels/*",
        "*://*.kayak.fr/stays*",
        "*://*.kayak.fr/stays/*",
        "*://*.kayak.es/hotels*",
        "*://*.kayak.es/hotels/*",
        "*://*.kayak.es/stays*",
        "*://*.kayak.es/stays/*",
        "*://*.priceline.com/relax/*",
        "*://*.priceline.com/*"
      ],
      "js": [
        "content-main.js"
      ],
      "world": "MAIN",
      "run_at": "document_start"
    },
    {
      "matches": [
        "*://*.agoda.com/*",
        "*://*.airbnb.co.uk/s/*",
        "*://*.airbnb.com/s/*",
        "*://*.airbnb.de/s/*",
        "*://*.airbnb.es/s/*",
        "*://*.airbnb.fr/s/*",
        "*://*.airbnb.it/s/*",
        "*://*.booking.com/searchresults*",
        "*://*.expedia.co.uk/*Hotel-Search*",
        "*://*.expedia.co.uk/*hotel-search*",
        "*://*.expedia.com/*Hotel-Search*",
        "*://*.expedia.com/*hotel-search*",
        "*://*.expedia.de/*Hotel-Search*",
        "*://*.expedia.de/*hotel-search*",
        "*://*.expedia.es/*Hotel-Search*",
        "*://*.expedia.es/*hotel-search*",
        "*://*.expedia.fr/*Hotel-Search*",
        "*://*.expedia.fr/*hotel-search*",
        "*://*.expedia.it/*Hotel-Search*",
        "*://*.expedia.it/*hotel-search*",
        "*://*.hotels.com/*Hotel-Search*",
        "*://*.hotels.com/*hotel-search*",
        "*://*.kayak.co.uk/hotels*",
        "*://*.kayak.co.uk/stays*",
        "*://*.kayak.com/hotels*",
        "*://*.kayak.com/stays*",
        "*://*.kayak.de/hotels*",
        "*://*.kayak.de/stays*",
        "*://*.kayak.es/hotels*",
        "*://*.kayak.es/stays*",
        "*://*.kayak.fr/hotels*",
        "*://*.kayak.fr/stays*",
        "*://*.kayak.it/hotels*",
        "*://*.kayak.it/stays*",
        "*://*.priceline.com/relax/*",
        "*://*.trip.com/hotels*",
        "*://*.trivago.co.uk/*",
        "*://*.trivago.com/*",
        "*://*.trivago.de/*",
        "*://*.trivago.es/*",
        "*://*.trivago.fr/*",
        "*://*.trivago.it/*"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/content.js"
      ]
    },
    {
      "matches": [
        "*://*.agoda.com/*",
        "*://*.airbnb.co.uk/rooms/*",
        "*://*.airbnb.com/rooms/*",
        "*://*.airbnb.de/rooms/*",
        "*://*.airbnb.es/rooms/*",
        "*://*.airbnb.fr/rooms/*",
        "*://*.airbnb.it/rooms/*",
        "*://*.booking.com/hotel/*",
        "*://*.expedia.co.uk/*",
        "*://*.expedia.com/*",
        "*://*.expedia.de/*",
        "*://*.expedia.es/*",
        "*://*.expedia.fr/*",
        "*://*.expedia.it/*",
        "*://*.hotels.com/*",
        "*://*.kayak.co.uk/hotels/*",
        "*://*.kayak.co.uk/stays/*",
        "*://*.kayak.com/hotels/*",
        "*://*.kayak.com/stays/*",
        "*://*.kayak.de/hotels/*",
        "*://*.kayak.de/stays/*",
        "*://*.kayak.es/hotels/*",
        "*://*.kayak.es/stays/*",
        "*://*.kayak.fr/hotels/*",
        "*://*.kayak.fr/stays/*",
        "*://*.kayak.it/hotels/*",
        "*://*.kayak.it/stays/*",
        "*://*.priceline.com/*",
        "*://*.trip.com/hotels/*",
        "*://*.trivago.co.uk/*",
        "*://*.trivago.com/*",
        "*://*.trivago.de/*",
        "*://*.trivago.es/*",
        "*://*.trivago.fr/*",
        "*://*.trivago.it/*"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/hotel-detail.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Transit Time Filter",
    "default_popup": "popup.html"
  }
}