Examine source code of Simple Grammar Checker

{
  "manifest_version": 2,
  "name": "Simple Grammar Checker",
  "version": "1.0",
  "description": "A basic grammar checker for text inputs.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "dictionary.js",
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5d3a9a02-ed87-49ec-a955-08021ab58d1e}"
    }
  }
}