Examine source code of Keyboard Text Copier

{
  "manifest_version": 3,
  "name": "Keyboard Text Copier",
  "version": "1.3.0",
  "description": "Copy web page text using only the keyboard. Activate with Ctrl+Shift+Period.",
  "browser_specific_settings": {
    "gecko": {
      "id": "keyboard-text-copier@bpedrazaa",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "activeTab",
    "clipboardWrite",
    "scripting",
    "storage"
  ],
  "options_page": "options.html",
  "commands": {
    "activate": {
      "suggested_key": {
        "default": "Ctrl+Shift+Period"
      },
      "description": "Activate Keyboard Text Copier"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "48": "icons/ktc_icon_48x48.png",
    "128": "icons/ktc_icon_128x128.png"
  }
}