How do I remove the status bar?

Never be afraid to read the code :-) Looking at org.netbeans.core.windows.view.ui.MainWindow::getCustomStatusLine(), it does this:

   private static JComponent getCustomStatusLine() {
       try {
           String fileName = Constants.CUSTOM_STATUS_LINE_PATH;
           if (fileName == null) {
               return null;
           }
           FileObject fo = FileUtil.getConfigFile(fileName);
           if (fo != null) {
               DataObject dobj = DataObject.find(fo);
               InstanceCookie ic = (InstanceCookie)dobj.getCookie(InstanceCookie.class);
               if (ic != null) {
                   return (JComponent)ic.instanceCreate();
               }
           }
       } catch (Exception e) {
           Exceptions.printStackTrace(e);
       }
       return null;
   }

Constants.CUSTOM_STATUS_LINE_PATH is defined as

System.getProperty("netbeans.winsys.status_line.path");

So, have a module which, in its ModuleInstall (or as a command-line parameter in their myApp.conf), does

System.setProperty("netbeans.winsys.status_line.path", "com/foo/com-foo-MyStatusBar.instance");

and in its layer file, does something like

<folder name="foo">
  <file name="com-foo-MyStatusBar.instance"/>
</folder>

and then a class

package com.foo;
public class MyStatusBar extends JLabel {
 public Dimension getPreferredSize() { return new Dimension(0,0); }
 public Dimension getMaximumSize() { return new Dimension(0,0); } //may not be necessary
}

and you should get a status bar whose preferred size is to have no size at all.

Note you will probably want to provide your own instance of StatusDisplayer in the default lookup so there is some way for things to display status unless you really don’t need it.

Another option (exception on Mac OS) is to move the status line to the main menu (it will use the space to the right of the last menu item) -

netbeans -Dnetbeans.winsys.statusLine.in.menuBar=true

or the equivalent System.setProperty() from a ModuleInstall