The override object is only included if you introduce extension overrides. When you use the Override method, the Gulp.js commands detect any HTML or Sass overrides and automatically include them in this file.
For example, if you override the _error.sass file of the Extension1 extension and run the gulp theme:deploy command, the theme development tools add the following override your theme’s manifest.json file as part of the deployment process:
//…
“override”: [
{
“src”: “Overrides/Extension1/Modules/MyExamplePDPExtension1/Sass/_error.scss”,
“dst”: “Extension1/Modules/MyExamplePDPExtension1/Sass/_error.scss”
},
//…