Examine source code of Link Safety Checker

{
  "manifest_version": 2,
  "name": "Link Safety Checker",
  "description": "Check external links against a safety service before navigation",
  "version": "1.0",
  "icons": {
    "64": "icons/icons-64.png",
    "128": "icons/icons-128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{6d0bc14e-7c9d-42bf-8618-8f88c4006f96}",
      "strict_min_version": "90.0"
    }
  }
}