TYPO3 Core

With https://review.typo3.org/c/Packages/TYPO3.CMS/+/73488 new content elements are automatically added to the "New content elements" wizard.

When you add a content element like this:

ExtensionManagementUtility::addTcaSelectItem(
    'tt_content',
    'CType',
    [
        'label' => 'LLL:EXT:examples/Resources/Private/Language/locallang.xlf:examples_dataprocdb_title',
        'value' => 'examples_dataprocdb',
        'icon' => 'mimetypes-x-content-table',
    ],
);

Therefore without a group it is added to the very top in the CType select field and to a tab with caption "-" in the wizard.

I would suggest to add it to the group "default" instead. The group name "default" implies that it is the default group indeed.