rwmb_meta_box_settings

This filter changes the settings of a meta box (field group) after the plugin normalizes the meta box and its fields. It runs for every meta box, before the meta box shows.

apply_filters( 'rwmb_meta_box_settings', $meta_box );

It has 1 parameter: $meta_box, the meta box settings. The fields are in $meta_box['fields'].

Use rwmb_meta_boxes to register or change meta boxes. Use this filter only when you need the normalized settings, for example, the full field settings with default values.

Example

Make all fields in a meta box read-only for non-admin users:

add_filter( 'rwmb_meta_box_settings', function ( $meta_box ) {
    if ( 'company-info' !== $meta_box['id'] || current_user_can( 'manage_options' ) ) {
        return $meta_box;
    }
    foreach ( $meta_box['fields'] as &$field ) {
        $field['attributes']['readonly'] = true;
    }
    return $meta_box;
} );