Examine source code of Snapdrop for Firefox

{
  "browser_action": {
    "default_icon": "sd.png"
  },
  "sidebar_action": {
    "default_icon": "sd.png",
    "default_panel": "popup/sidebar.html",
    "open_at_install": false
  },
  "description": "Share files between devices in your local network",
  "homepage_url": "https://github.com/ueen/SnapdropFirefoxAddon",
  "manifest_version": 2,
  "name": "Snapdrop Browser Extension",
  "version": "1.9.8",
  "options_ui": {
    "page": "options/options.html"
  },
  "content_security_policy": "script-src 'self' https://snapdrop.net; object-src 'self'",
  "permissions": [
    "notifications",
    "clipboardWrite",
    "downloads",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3af274cf-1fa9-47bc-9167-1f2251fee500}"
    }
  },
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "snapdrop/network.js",
      "snapdrop/connect.js",
      "background.js"
    ]
  },
  "icons": {
    "128": "sd.png"
  }
}