Examine source code of OpenTitles

{
  "manifest_version": 3,
  "name": "OpenTitles",
  "short_name": "OpenTitles",
  "author": "Floris de Bijl",
  "description": "Show the changes to titles for over 40 news outlets.",
  "version": "2.17.0",
  "icons": {
    "16": "icons/logo16.png",
    "48": "icons/logo48.png",
    "128": "icons/logo128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{46e1c7cd-4bfa-4bdb-949e-e8103f99dd9a}",
      "strict_min_version": "76.0"
    }
  },
  "action": {
    "default_icon": "icons/logo48.png",
    "default_title": "Click to suggest this website to OpenTitles",
    "default_popup": "popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.nu.nl/*",
        "https://*.nos.nl/*",
        "https://*.jeugdjournaal.nl/*",
        "https://*.ad.nl/*",
        "https://*.bd.nl/*",
        "https://*.ed.nl/*",
        "https://*.tubantia.nl/*",
        "https://*.bndestem.nl/*",
        "https://*.pzc.nl/*",
        "https://*.destentor.nl/*",
        "https://*.gelderlander.nl/*",
        "https://*.telegraaf.nl/*",
        "https://*.tweakers.net/*",
        "https://*.nrc.nl/*",
        "https://*.volkskrant.nl/*",
        "https://*.rtlnieuws.nl/*",
        "https://*.trouw.nl/*",
        "https://*.parool.nl/*",
        "https://*.limburger.nl/*",
        "https://*.fd.nl/*",
        "https://*.dvhn.nl/*",
        "https://*.hartvannederland.nl/*",
        "https://*.lc.nl/*",
        "https://*.rd.nl/*",
        "https://*.bnr.nl/*",
        "https://*.elsevierweekblad.nl/*",
        "https://*.abcnews.go.com/*",
        "https://*.cbsnews.com/*",
        "https://*.cnn.com/*",
        "https://*.msnbc.com/*",
        "https://*.nytimes.com/*",
        "https://*.latimes.com/*",
        "https://*.usatoday.com/*",
        "https://*.wsj.com/articles/*",
        "https://*.washingtonpost.com/*",
        "https://*.vice.com/*",
        "https://*.huffingtonpost.com/*",
        "https://*.tmz.com/*",
        "https://*.newsweek.com/*",
        "http://*.time.com/*",
        "https://*.theguardian.com/*",
        "https://*.reuters.com/*"
      ],
      "js": [
        "OpenTitlesMainScript.js"
      ],
      "css": [
        "style/OpenTitles.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "background": {
    "scripts": [
      "OpenTitlesBackground.js"
    ]
  },
  "host_permissions": [
    "https://api.opentitles.info/*"
  ],
  "permissions": [
    "tabs"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "media.json"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    }
  ]
}