Examine source code of Android scroll top

{
  "manifest_version": 2,
  "name": "Android scroll top",
  "description": "Adds a menu item on Android to scroll to the top of the page. \nOn desktop it adds a button.",
  "version": "1.0.2",
  "author": "DaveRo",
  "applications": {
    "gecko": {
      "id": "android_scroll_top@davero.addons.mozilla.org"
    }
  },
  "browser_specific_settings": {
    "gecko_android": {},
    "gecko": {
      "id": "android_scroll_top@davero.addons.mozilla.org"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "scripts": [
      "background_top.js"
    ]
  },
  "permissions": [
    "menus",
    "tabs"
  ],
  "browser_action": {
    "browser_style": true,
    "default_title": "Scroll to top",
    "default_icon": "Go-up.svg"
  }
}