Examine source code of ScholarKey

{
  "manifest_version" : 3 ,
  "name" : "ScholarKey",
  "version" : "3.4",
  "description" : "Next to every DOI on the web: Wikipedia citation count and configurable access links.",
  "permissions" : [
    "storage" 
  ],
  "host_permissions" : [
    "<all_urls>" 
  ],
  "action" : {
    "default_title" : "ScholarKey settings",
    "default_popup" : "popup.html",
    "default_icon" : {
      "48" : "icons/icon_48.png",
      "128" : "icons/icon_128.png"
    }
  },
  "icons" : {
    "48" : "icons/icon_48.png",
    "128" : "icons/icon_128.png"
  },
  "content_scripts" : [
    {
      "matches" : [
        "<all_urls>" 
      ],
      "js" : [
        "content.js" 
      ],
      "css" : [
        "content.css" 
      ],
      "run_at" : "document_idle" 
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "scholarkey@firefox",
      "strict_min_version": "112.0"
    }
  }
}