Examine source code of Meta Finder

{
  "name": "Meta Finder",
  "browser_specific_settings": {
    "gecko": {
      "id": "certosinolab@gmail.com",
      "strict_min_version": "60.0"
    }
  },
  "description": "Extension to find relevant meta tags on web pages",
  "version": "1.0.2",
  "manifest_version": 2,
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage",
    "activeTab",
    "unlimitedStorage"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ]
}