Examine source code of CERTIFICADO J4

{
  "manifest_version": 2,
  "name": "CERTIFICADO J4",
  "version": "1.1.1",
  "description": "CERTIFICADO J4",
  "permissions": [
    "<all_urls>",
    "webRequest",
    "tabs"
  ],
  "content_scripts": [
    {
      "all_frames": true,
      "run_at": "document_idle",
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{583999ce-69d9-412f-aaaf-78da4b23ceba}"
    }
  }
}