Examine source code of Procrastination Blocker

{
  "manifest_version": 2,
  "name": "Procrastination Blocker",
  "version": "1.0",
  "description": "Extension to block certain time wasting websites.",
  "icons": {
    "16": "icons/on16.png",
    "32": "icons/on32.png",
    "48": "icons/on48.png",
    "128": "icons/on128.png"
  },
  "permissions": [
    "storage",
    "contextMenus"
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "browser_action": {
    "default_title": "Toggle extension",
    "default_icon": {
      "16": "icons/off16.png",
      "32": "icons/off32.png",
      "48": "icons/off48.png",
      "128": "icons/on128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "procrastinationblocker@local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}