Examine source code of Lokia - Dual Subtitles & Language Learning

{
  "manifest_version": 2,
  "name": "Lokia - Dual Subtitles & Language Learning",
  "version": "1.4.3",
  "description": "Dual subtitles on YouTube and Netflix. Click words to translate, save vocabulary, and review on lokia-app.com.",
  "permissions": [
    "storage",
    "activeTab",
    "tabs",
    "https://api.lokia-app.com/*",
    "https://www.youtube.com/*",
    "https://www.netflix.com/*"
  ],
  "web_accessible_resources": [
    "assets/icons/*",
    "assets/flags/*"
  ],
  "icons": {
    "16": "assets/icons/icon16.png",
    "48": "assets/icons/icon48.png",
    "128": "assets/icons/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "src/config.js",
        "src/content/dualSubtitles.js",
        "src/content/dualSubsPageFetch.js",
        "src/content/content.js",
        "src/content/playerSettings.js"
      ],
      "css": [
        "src/styles/youtube-content.css"
      ]
    },
    {
      "matches": [
        "https://www.netflix.com/*",
        "https://netflix.com/*",
        "*://*.netflix.com/*"
      ],
      "js": [
        "src/content/netflix/netflixPlayerApi.js"
      ],
      "world": "MAIN",
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://www.netflix.com/*",
        "https://netflix.com/*",
        "*://*.netflix.com/*"
      ],
      "js": [
        "src/config.js",
        "src/content/dualSubtitles.js",
        "src/content/netflix/netflixShared.js",
        "src/content/netflix/netflixDualSubs.js",
        "src/content/playerSettings.js",
        "src/content/netflix/netflix.js"
      ],
      "css": [
        "src/styles/netflix-content.css"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "src/config.js",
      "src/background/translate.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "src/popup/popup.html",
    "default_icon": {
      "16": "assets/icons/icon16.png",
      "32": "assets/icons/icon32.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "lokia@lokia-app.com",
      "strict_min_version": "128.0"
    }
  }
}