Currently, the empty state message of a Table in Codex-PHP is hardcoded as cdx-table-no-data-message.
It would be good to be able to customize this message with arbitrary HTML.
There are currently TableBuilder::setFooter( string $footer ) and TableBuilder::setHeaderContent( string $headerContent ) methods, so perhaps a new TableBuilder::setEmptyStateContent( string $emptyStateContent ) would be appropriate.