Examine source code of PubFinder

{
  "manifest_version" : 3 ,
  "name" : "PubFinder",
  "version" : "1.1",
  "description" : "Scans the page for DOIs/DMEIs, organizes articles into folders and manages favorites.",
  "permissions" : [
    "activeTab" ,
    "storage" ,
    "scripting" 
  ],
  "host_permissions" : [
    "https://api.unpaywall.org/*" ,
    "https://api.crossref.org/*" ,
    "https://doi.org/*" 
  ],
  "icons" : {
    "48" : "icon-48.png",
    "128" : "icon-128.png"
  },
  "action" : {
    "default_popup" : "popup.html",
    "default_icon" : {
      "48" : "icon-48.png",
      "128" : "icon-128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "pubfinder@local",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}