Examine source code of Search For MadAsMaths

{
  "manifest_version": 2,
  "name": "Search For MadAsMaths",
  "version": "1.1",
  "description": "Adds a search bar to madasmaths.com",
  "icons": {
    "48": "icons/mm+-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://madasmaths.com/*"
      ],
      "js": [
        "mm.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d8b1ae55-e733-4f31-82bf-a978cf3d402a}"
    }
  }
}