Examine source code of Brainly Block

{
  "name": "Brainly Block",
  "description": "Bloqueia o PayWall do Brainly",
  "version": "1.0",
  "manifest_version": 2,
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "tabs",
    "notifications",
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://*.brainly.com.br/*"
      ],
      "js": [
        "background.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{6e935e8c-5aa9-4a50-aa4a-e8e0b335cdc5}"
    }
  }
}