Examine source code of Rentable.be

{
  "name": "Rentable.be",
  "version": "1.1",
  "description": "Calcul du rendement sur Immoweb",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": [
        "https://*.immoweb.be/**/Buy.Estate.cfm*",
        "https://*.immoweb.be/**/a-vendre/*",
        "https://*.immoweb.be/**/for-sale/*",
        "https://*.immoweb.be/**/te-koop/*",
        "https://biddit.be/**/catalog/detail/*",
        "https://*.biddit.be/**/catalog/detail/*"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "https://rentable.be/"
  ],
  "icons": {
    "16": "images/icon-16x16.png",
    "32": "images/icon-32x32.png",
    "48": "images/icon-48x48.png",
    "128": "images/icon-128x128.png"
  },
  "web_accessible_resources": [
    "index.html",
    "css/",
    "fonts/",
    "img/",
    "js/"
  ]
}