This is at client/public/umbraco-package.json (I am useing the opiniated-package-started setup) It is also my bed time so I will be back in like 8 or 9 hours to answer any followups. {   "id": "TestPackage",   "name": "TestPackage",   "version": "0.0.0",   "allowTelemetry": true,   "extensions": [     {       "name": "Test Bundle",       "alias": "Test.Bundle",       "type": "bundle",       "js": "/App_Plugins/TestPackage/test-package.js"     },     {       "type": "section",       "alias": "Test.Package",       "name": "Test Package",       "meta": {         "label": "Test Package Section",         "pathname": "test-package-section"       }     }   ] }

That is a bit of a different file. You should also have a package.json somewhere that would look something like this:

{
  "name": "umbraco-extension",
  "private": true,
  "version": "0.0.0",
  "type": "module",
  "scripts": {
    "watch": "tsc && vite build --watch",
    "build": "tsc && vite build",
    "generate-client": "node scripts/generate-openapi.js https://localhost:44339/umbraco/swagger/umbracoextension/swagger.json"
  },
  "devDependencies": {
    "@hey-api/openapi-ts": "^0.85.0",
    "@umbraco-cms/backoffice": "^UMBRACO_VERSION_FROM_TEMPLATE",
    "chalk": "^5.6.2",
    "cross-env": "^10.1.0",
    "node-fetch": "^3.3.2",
    "typescript": "^5.9.3",
    "vite": "^7.1.9"
  }
}

In the scripts, you should also see the watch there. You should be able to run

npm run watch

in order to automatically build whenever you make a change to your files

It looks like the Lotte Pitcher's Opionionated Package Starter does not include a normal package.json anywhere in the project and doing a solution wide search for "umbraco-extension" finds nothing