Examine source code of CleanCopy

{
  "manifest_version": 2,
  "name": "Clean Copy",
  "version": "1.0",
  "description": "Prevents websites from adding extra text when copying.",
  "permissions": [
    "activeTab",
    "clipboardWrite",
    "clipboardRead"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{dd54effd-bd86-4146-9fe4-a5686b687f9e}"
    }
  }
}