Examine source code of MyTentacles

{
  "manifest_version": 2,
  "name": "Tentacles",
  "version": "1.0",
  "description": "Tentacles",
  "icons": {
    "16": "border-16.png",
    "48": "border-48.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "border-16.png",
    "default_popup": "./popup/popup.html",
    "default_title": "Tentacles"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "tentacles.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ]
}