Examine source code of Pokemon ShowdownSync

{
  "manifest_version": 2,
  "name": "ShowdownSync",
  "version": "1.0.1",
  "description": "Synchronise les teams sur pokemonshowdown.com",
  "permissions": [
    "cookies",
    "storage",
    "<all_urls>",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "showdownsync@example.org"
    }
  },
  "browser_action": {
    "default_icon": {
      "37": "icons/ico.png"
    },
    "default_popup": "popup.html",
    "default_title": "ShowdownSync"
  },
  "icons": {
    "37": "icons/ico.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://play.pokemonshowdown.com/*"
      ],
      "js": [
        "sync_teams.js"
      ]
    }
  ]
}