Examine source code of Telegram Send

{
  "$schema": "http://json.schemastore.org/webextension",
  "manifest_version": 2,
  "name": "Telegram Send",
  "version": "1.0.1",
  "description": "Quickly share media and links on the web to telegram groups.",
  "author": "Nikita Stefaniak",
  "homepage_url": "https://github.com/phaux/telegram-send",
  "icons": {
    "48": "./telegram.svg",
    "96": "./telegram.svg"
  },
  "permissions": [
    "https://api.telegram.org/*",
    "menus",
    "storage",
    "notifications"
  ],
  "browser_action": {
    "default_icon": "./telegram.svg"
  },
  "page_action": {
    "default_icon": "./telegram.svg",
    "default_title": "Send to Telegram"
  },
  "background": {
    "scripts": [
      "./background/index.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "./content_scripts/index.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options_ui/index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "telegram-send@phaux.github.io"
    }
  }
}