Examine source code of Ctrl + C : Copy Text only

{
  "manifest_version": 3,
  "name": "Ctrl + C: Copy Text not media",
  "version": "1.1",
  "description": "Copy the textual content of the website to the clipboard excluding images, gifs, etc.",
  "browser_specific_settings": {
    "gecko": {
      "id": "justdonotmailmewontwork@me.com"
    }
  },
  "permissions": [
    "activeTab",
    "scripting",
    "clipboardWrite"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "action": {
    "default_title": "Copy Text Content",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  }
}