Examine source code of Papeer.tech

{
  "manifest_version": 3,
  "name": "Papeer.tech",
  "version": "1.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "{0934fcad-0a1e-4ecd-9737-9a580eb05967}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "Send the current page to your e-reader",
  "icons": {
    "16": "images/logo-x16.png",
    "48": "images/logo-x48.png",
    "128": "images/logo-x128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "action": {
    "default_title": "Open on Papeer.tech",
    "default_icon": {
      "16": "images/logo-x16.png",
      "48": "images/logo-x48.png",
      "128": "images/logo-x128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}