Examine source code of LGeL is Back

{
  "manifest_version": 2,
  "name": "LGeL is Back",
  "version": "1",
  "description": "Remets en état la page de jeu avant la mise à jour du 04/12/2019 avec une seule feuille de style CSS.",
  "author": "Firmament",
  "content_scripts": [
    {
      "matches": [
        "*://www.loups-garous-en-ligne.com/jeu/*"
      ],
      "css": [
        "lgelisback.css"
      ]
    }
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "lgelisback.png",
      "32": "lgelisback.png"
    },
    "default_title": "LGeL is Back",
    "default_popup": "https://extensions-lgel.com/lgelisback.php"
  },
  "icons": {
    "48": "lgelisback.png",
    "96": "lgelisback.png"
  }
}