LibreOffice 7.2 Help
To move a numbered or bulleted list paragraph down one list level, click at the beginning of the paragraph, and then press Tab.
To move a numbered or bulleted list paragraph up one list level, click at the beginning of the paragraph, and then press Shift+Tab.
To insert a tab between the number or bullet and the paragraph text, click at the beginning of the paragraph, and then press CommandCtrl+Tab.