Examine source code of Search Engine Ad Remover

{
  "manifest_version": 2,
  "name": "Search Engine Ad Remover",
  "version": "2.1.0",
  "description": "Removes ads from the following search engines: Google, DuckDuckGo, Bing, Startpage",
  "content_scripts": [
    {
      "matches": [
        "https://www.google.com/*",
        "https://duckduckgo.com/*",
        "https://www.bing.com/*",
        "https://www.startpage.com/*"
      ],
      "js": [
        "remover.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@justmage.de"
    }
  }
}