rushstack/apps/api-extractor/config/rush-project.json

{
  "extends": "@rushstack/heft-node-rig/profiles/default/config/rush-project.json",

  "operationSettings": [
    {
      "operationName": "_phase:build",
      "outputFolderNames": [".heft"]
    },
    {
      "operationName": "_phase:test",
      "outputFolderNames": ["coverage"]
    }
  ]
}