When to use Routing with Bootstrap 5 PHP?

After reading a Team instruction to use Site Root in development this morning I changed and saved the settings for my PHP project already underway for two weeks to this.

I refreshed settings and pages and then made some new php pages in my local environment. But these new pages do not have an “Auto Add Base” information in the head.

<!doctype html>
<html>
<head>
<script src="/dmxAppConnect/dmxAppConnect.js"></script>
<meta charset="UTF-8">
<title>Untitled Document</title>

<link rel="stylesheet" href="/css/bootstrap-icons.css" />
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link rel="stylesheet" href="/bootstrap/5/litera/bootstrap.min.css" />
<script src="/js/jquery-3.5.1.slim.min.js"></script>
<link rel="stylesheet" href="/css/style.css" />
</head>
<body is="dmx-app" id="aaaa">
<script src="/bootstrap/5/js/bootstrap.bundle.min.js"></script>
</body>
</html>

When I had the Project Setting before with “Use Routing” OFF/Disabled the php pages were written with this Base href , which is opposite behavior from what the docs are saying

<meta name="ac:base" content="/newtrainings">
<base href="/newtrainings/">

If I do not need URL REWRITING in my PHP project then I’ll reset my project to NOT enable “Use Routing”.

But why is the setting working in reverse of what the docs say?

Which settings works in reverse exactly?
When these two are enabled:

the base tags will be added on your pages, when you create and save them:

<meta name="ac:base" content="/newtrainings">
<base href="/newtrainings/">

when this is disabled:

after disabling it, every new page created and saved won't have this tag.

This option will not automatically remove the base tags already added on all your pages in the project before you turned off.