Examine source code of AddFastlyDebug

{
  "manifest_version": 2,
  "name": "AddFastlyDebug",
  "version": "0.1.1",
  "description": "Add Fastly Debug to all requests",
  "permissions": [
    "<all_urls>",
    "webRequest",
    "webRequestBlocking"
  ],
  "icons": {
    "48": "icons/fastly-debug.png"
  },
  "background": {
    "scripts": [
      "fastly-debug.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2fe0774c-613e-4a7d-bcae-afb503364f72}"
    }
  }
}