Examine source code of PDF Always Open

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "version": "1.0.6",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "src/headers.js",
      "src/background.js"
    ]
  },
  "icons": {
    "128": "icon_128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c142022f-3fea-4cef-a9ed-462cd325347d}"
    }
  }
}