Examine source code of Open in txtify.it

{
  "manifest_version": 2,
  "name": "Open in txtify.it",
  "version": "1.0.0",
  "author": "Luana",
  "description": "Add open in txtify.it button and right-click menu",
  "homepage_url": "https://github.com/luanacc/txtify",
  "icons": {
    "16": "icons/txtify-16.png",
    "32": "icons/txtify-32.png",
    "48": "icons/txtify-48.png"
  },
  "browser_action": {
    "default_icon": "icons/txtify-48.png",
    "default_title": "Open in txtify.it"
  },
  "permissions": [
    "contextMenus",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e0bf2bb7-a476-4aff-83c6-87fcb48fb2eb}"
    }
  }
}