Examine source code of memefy

{
  "name": "memefy",
  "version": "1.0.1",
  "description": "Turn your frown upside down.",
  "icons": {
    "128": "128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "declarativeContent",
    "storage"
  ],
  "page_action": {
    "default_popup": "popup.html"
  },
  "manifest_version": 2
}