Examine source code of Accessibility Validator

{
  "manifest_version": 2,
  "name": "Accessibility Validator",
  "version": "1.0",
  "description": "Validates the accessibility of the website's content.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "accessibility_validator_extension@gmail.com"
    }
  }
}