Strange error when updating 5.23.0 Joomla
I have updated the lines 824 en 825 in CRM/CORE/Resources.php with a dirty solution:

$map = ['bower_components' => str_replace('Joomla/Joomla','Joomla',rtrim(Civi::paths()->getUrl('[civicrm.bower]/.', 'absolute'), '/')),
      'packages' => str_replace('Joomla/Joomla','Joomla',rtrim(Civi::paths()->getUrl('[civicrm.packages]/.', 'absolute'), '/')),
    ];

It can not be the real solution but the site is now working and i have just completed succesful the database-upgrade. Maybe only a problem with sites on Windows.