Examine source code of anitrack

{
  "manifest_version": 2,
  "name": "anitrack",
  "version": "2.0.9resigned1",
  "description": "Synchronizes watched anime/read manga with MyAnimeList or Kitsu",
  "homepage_url": "https://github.com/TSedlar/anitrack",
  "applications": {
    "gecko": {
      "id": "mal-scrobble@mozilla.org",
      "strict_min_version": "45.0"
    }
  },
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "background": {
    "scripts": [
      "bundle.js"
    ]
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": "images/icon48.png",
    "default_title": "anitrack",
    "default_popup": "popup/popup.html"
  },
  "permissions": [
    "*://*.myanimelist.net/*",
    "*://*.kitsu.io/*",
    "webNavigation",
    "notifications",
    "tabs",
    "activeTab",
    "storage",
    "*://*.9anime.to/watch/*",
    "*://*.9anime.is/watch/*",
    "*://*.9anime.ch/watch/*",
    "*://*.amazon.com/*/dp/*",
    "*://*.animepahe.com/play/*/*",
    "*://*.animeseries.co/watch/*",
    "*://*.chia-anime.tv/*episode*",
    "*://*.crunchyroll.com/*episode*",
    "*://*.crunchyroll.com/*/*episode*",
    "*://app.emby.media/*/videoosd.html",
    "*://*.funimation.com/shows/*",
    "*://*.gogoanime.io/*episode*",
    "*://*.gogoanime.se/*episode*",
    "*://*.gogoanime.tv/*episode*",
    "*://*.hulu.com/watch/*",
    "*://*.jaiminisbox.com/reader/read/*",
    "*://*.kissanime.ru/Anime/*",
    "*://*.kissanime.ac/Anime/*",
    "*://*.kissanime.to/Anime/*",
    "*://*.kissmanga.com/Manga/*/*",
    "*://*.mangadex.org/chapter/*/*",
    "*://*.mangaeden.com/*/*/*/*/*",
    "*://*.fanfox.net/manga/*/*/*/*",
    "*://*.mangapark.me/manga/*/*/*/*",
    "*://*.mangareader.net/*/*",
    "*://*.mangarock.com/manga/*/chapter/*",
    "*://*.readms.net/r/*/*/*",
    "*://*.masterani.me/anime/watch/*",
    "*://*.netflix.com/watch/*",
    "*://*.twist.moe/a/*",
    "*://*.viz.com/*/*/*/*",
    "*://*.vrv.co/watch/*"
  ]
}