Examine source code of SharePoint Word Redirect

{
  "manifest_version": 2,
  "name": "SharePoint Word Redirect",
  "version": "1.0",
  "description": "Rewrite SharePoint Word links to open in desktop app",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b002b8fd-d949-4ad5-8cbb-2dbd0307a50e}"
    }
  }
}