Examine source code of Code Color Preview

{
  "manifest_version": 2,
  "name": "Code Color Preview",
  "version": "2.2.0",
  "description": "Shows color previews next to hex and RGB codes in web pages",
  "permissions": [
    "storage",
    "activeTab",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "code-color-preview@lzhecz.github.com",
      "strict_min_version": "58.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "113.0"
    }
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.svg",
    "default_title": "Code Color Preview Settings"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "48": "icon.svg"
  }
}