Examine source code of Page Color Picker

{
  "manifest_version": 2,
  "name": "Page Color Picker",
  "version": "1.0.0",
  "description": "Pick colors from the current tab. Click on the preview to copy HEX/RGB.",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "clipboardWrite"
  ],
  "browser_action": {
    "default_title": "Page Color Picker",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "109.0",
      "id": "{76e30a03-1189-4625-b123-9f667fa6ed05}"
    }
  }
}