Quasar: Remove parameter from default manifest

On my vue.js PWA, there's a manifest.json generated by Quasar.

From what I understand, the default manifest generated by Quasar is overwritten with parameters from my quasar.conf.js:

manifest: {
        name: `App name`,
        short_name: `app short name`,
        description: `Application description`,
        display: 'fullscreen',
        orientation: 'any',
        background_color: '#ffffff',
        theme_color: '#000000',
        icons: [...]
}

The resulting compiled manifest looks like this:

{
    "name": "App name",
    "short_name": "app short name",
    "description": "Application description",
    "display": "fullscreen",
    "start_url": ".",
    "orientation": "any",
    "background_color": "#ffffff",
    "theme_color": "#000000",
    "icons": [...],
}

What I want to do now is to remove a parameter completely from the default manifest.

Specifically, I want the parameter start_url not to show up on my compiled manifest. I can modify it by adding this parameter to the quasar.conf.js but I cannot completely remove it.

Any hints how to completely remove start_url from the compiled manifest?