Examine source code of freeman-startpage

{
  "manifest_version": 3,
  "name": "freeman-startpage",
  "short_name": "freeman-startpage",
  "version": "1.2",
  "description": "Overrides the browsers newtab page with a custom startpage.",
  "author": "nkosiyabo",
  "icons": {
    "64": "img/icon64.png"
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "frizamoyo@frizamoyo"
    }
  }
}