Hi Martin,
The text "Meta Box Title" is the default title which displays when the meta box has an empty title. If you use the code to show the meta box and fields, leave the title with a space to remove it.
$meta_boxes[] = array(
'id' => 'meta-box-id',
'title' => ' ',
'post_types' => 'post_type',
...
Or use this custom CSS code in the admin area to hide it.
#meta-box-id h2.hndle {
opacity: 0;
}
See https://share.getcloudapp.com/12urWRyB.
Or use the meta box setting 'style' => 'seamless'
remove the wrapper box and display fields seamlessly. Follow the documentation https://docs.metabox.io/creating-meta-boxes/#meta-box-settings.