Examine source code of Estimate & Invoice Maker

{
  "browser_specific_settings": {
    "gecko": {
      "id": "estimatesappext@iwtmobile"
    }
  },
  "manifest_version": 3,
  "name": "Estimate & Invoice Maker",
  "description": "Redirect to Create Invoice or Estimate.",
  "version": "0.1",
  "permissions": [
    "declarativeNetRequestWithHostAccess"
  ],
  "host_permissions": [
    "*://*.estimatesapp.com/"
  ],
  "declarative_net_request": {
    "rule_resources": [
      {
        "id": "ruleset",
        "enabled": true,
        "path": "redirect-rules.json"
      }
    ]
  },
  "icons": {
    "32": "icon.png",
    "64": "icon@2x.png"
  },
  "action": {
    "default_popup": "popup.html"
  },
  "web_accessible_resources": [
    {
      "resources": [
        "redirectTarget.html"
      ],
      "matches": [
        "*://estimatesapp.com/*"
      ]
    }
  ]
}