Meta walker: relabel category/tag entries

add_action( 'tribe_pre_get_view', 'change_custom_field_meta_label' );

function change_custom_field_meta_label() {
    tribe_set_meta_label( 'tribe_event_tag', 'NEW LABEL!', 'meta' );
    tribe_set_meta_label( 'tribe_event_category', 'NEW LABEL!', 'meta' );
}