Examine source code of DevelopDashboard Local Bridge

{
  "manifest_version" : 3 ,
  "name" : "DevelopDashboard Local Bridge",
  "version" : "0.1.2",
  "description" : "Let DevelopDashboard tools reach localhost and custom local hostnames (e.g. develop.test) via your browser.",
  "browser_specific_settings": {
    "gecko": {
      "id": "local-bridge@developdashboard.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions" : [
    "storage" 
  ],
  "host_permissions" : [
    "http://localhost/*" ,
    "https://localhost/*" ,
    "http://127.0.0.1/*" ,
    "https://127.0.0.1/*" ,
    "http://[::1]/*" ,
    "https://[::1]/*" 
  ],
  "optional_host_permissions" : [
    "http://*/*" ,
    "https://*/*" 
  ],
  "background" : {
    "scripts" : [
      "api.js" ,
      "background.js" 
    ],
    "service_worker" : "background.js" 
  },
  "icons" : {
    "16" : "icons/icon-16.png",
    "32" : "icons/icon-32.png",
    "48" : "icons/icon-48.png",
    "128" : "icons/icon-128.png"
  },
  "action" : {
    "default_title" : "DevelopDashboard Local Bridge",
    "default_popup" : "popup.html",
    "default_icon" : {
      "16" : "icons/icon-16.png",
      "32" : "icons/icon-32.png",
      "48" : "icons/icon-48.png"
    }
  },
  "content_scripts" : [
    {
      "matches" : [
        "http://localhost/*" ,
        "https://localhost/*" ,
        "http://127.0.0.1/*" ,
        "https://127.0.0.1/*" ,
        "https://developdashboard.com/*" ,
        "https://*.developdashboard.com/*" 
      ],
      "js" : [
        "content.js" 
      ],
      "run_at" : "document_start" 
    }
  ]
}