Examine source code of Tab Lock

{
  "manifest_version": 2,
  "name": "Tab Lock",
  "version": "1.0",
  "description": "Lock tabs and prevent them from being closed.",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_icon": {
      "48": "icon48.png"
    },
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{0f84bdbf-391a-4f85-bc7f-ea86e79b5e26}"
    }
  }
}