Examine source code of Trumblr

{
  "manifest_version": 2,
  "name": "Trumblr",
  "short_name": "Trumblr",
  "description": "The low-energy so-called \"journalists\" can't even get the Prime Minister of Australia's name right. Sad!'",
  "version": "1.1resigned1",
  "author": "Samuel Janda",
  "homepage_url": "https://www.simpleprogramming.com.au/2017/04/06/trumblr",
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "permissions": [
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "jquery-3.2.0.slim.min.js",
        "script.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "background": {
    "scripts": [
      "jquery-3.2.0.slim.min.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2abf98a5-c3d9-4d1d-affe-4cb3cd84fa01}"
    }
  }
}