Examine source code of Checky - Contrast Checker

{
  "manifest_version": 2,
  "name": "Checky - Contrast Checker",
  "version": "1.0",
  "description": "Check WCAG colour contrast between two colours",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "checky@mihaigmnd",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "browser_action": {
    "default_icon": "icon.svg",
    "default_popup": "popup.html"
  }
}