Datetime only time

I would like to use the datetime field but only for choosing a time, without the datepicker. Is that possble?

In the previous version Grav was provided without datepicker for date field. Now you could modify the field o replace it with a new custom date field

Thanks for the hint. Any idea how exactly I can modify the field?

You can change some lines in :
system\blueprints\pages\default.yaml

        header.date:
          type: datetime
          label: PLUGIN_ADMIN.DATE
          toggleable: true
          help: PLUGIN_ADMIN.DATE_HELP