Examine source code of Nano Gestures

{
  "manifest_version": 2,
  "name": "Nano Gestures",
  "version": "0.3.8resigned1",
  "description": "Adds four basic mouse gestures for browser navigation.",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "author": "Rotem Dan",
  "homepage_url": "https://github.com/rotemdan/NanoGestures",
  "background": {
    "scripts": [
      "browser-polyfill.min.js",
      "common.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "browser-polyfill.min.js",
        "common.js",
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": true,
      "match_about_blank": true
    }
  ],
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "permissions": [
    "storage",
    "tabs",
    "sessions",
    "browserSettings"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{12cb0472-fcaf-408e-bef8-55cb359c38c7}"
    }
  }
}