Examine source code of narou-select

{
  "manifest_version": 3,
  "name": "narou-select",
  "version": "1.0",
  "author": "nut1414",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "64": "icon/64.png",
    "128": "icon/128.png"
  },
  "description": "Click to select content of narou!",
  "permissions": [
    "activeTab",
    "contextMenus",
    "clipboardWrite",
    "scripting"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://ncode.syosetu.com/*/*"
      ],
      "js": [
        "narou.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_icon": {
      "16": "icon/16.png",
      "32": "icon/32.png",
      "48": "icon/48.png",
      "64": "icon/64.png",
      "128": "icon/128.png"
    },
    "default_title": "narou select copy"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c33dcda9-dad7-4506-aecd-52589b71ce6d}"
    }
  }
}