Examine source code of fckw3

{
  "description": "Hide all w3schools results from query.",
  "manifest_version": 2,
  "name": "FckW3",
  "version": "1.4",
  "homepage_url": "https://github.com/heygema/fckw3",
  "icons": {
    "48": "icons/fckw3-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.google.com/*",
        "*://*.duckduckgo.com/*"
      ],
      "js": [
        "fckw3.js"
      ]
    }
  ]
}