Examine source code of Unchained

{
  "manifest_version": 2,
  "name": "Unchained",
  "version": "0.5",
  "description": "Websites blocking",
  "icons": {
    "16": "images/unchained-logo-16.png",
    "48": "images/unchained-logo-48.png",
    "128": "images/unchained-logo-128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "http://*/*",
        "https://*/*"
      ]
    }
  ],
  "permissions": [
    "tabs"
  ],
  "web_accessible_resources": [
    "blocked.html",
    "block.html"
  ],
  "browser_action": {
    "default_icon": {
      "16": "images/clock-icon-16.png",
      "24": "images/clock-icon-24.png",
      "32": "images/clock-icon-32.png"
    },
    "default_popup": "popup.html"
  }
}