Examine source code of Site Blocker V2

{
  "manifest_version": 2,
  "name": "Site Blocker V2",
  "version": "1.3",
  "description": "Blocks distracting websites. Now with schedule and temporary unblock!",
  "permissions": [
    "storage",
    "notifications",
    "webRequest",
    "webRequestBlocking"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": "icons/logo_64.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "icons": {
    "32": "icons/logo_32.png",
    "64": "icons/logo_64.png",
    "128": "icons/logo_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{aed8ba6d-c522-4ddf-a799-9d27fe3f7764}"
    }
  }
}