Examine source code of NNStickers

{
  "manifest_version": 2,
  "name": "NN Stickers",
  "version": "1.0",
  "description": "Show NN stickers.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "NN@aparat.com",
      "strict_min_version": "58.0"
    }
  }
}