Examine source code of Power Blocker

{
  "name": "Power Blocker",
  "browser_specific_settings": {
    "gecko": {
      "id": "ag29000000@gmail.com",
      "strict_min_version": "42.0"
    }
  },
  "version": "0.0.1",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "logo-sm.png"
  },
  "icons": {
    "16": "logo-sm.png",
    "48": "logo-sm.png",
    "128": "logo-lg.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}