Examine source code of PX Ruler

{
  "name": "Extension",
  "description": "Extension",
  "version": "6.72.3",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "home.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "icons": {
    "16": "icon/logo.png",
    "32": "icon/logo.png",
    "48": "icon/logo.png",
    "128": "icon/logo.png"
  },
  "permissions": [
    "clipboardRead"
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [
          "technicalAndInteraction"
        ]
      },
      "id": "{2cbe4a7f-696e-4f10-90e5-8241ed32cc2c}"
    }
  }
}