It means that Deliveroo has received your authorization to withhold the union association contribution, as notified by the union organization to which you belong and in compliance with the CCNL Rider. This amount is withheld after the application of your tax regime and you will see it in your payslip under the voice Trattenuta ai sensi dell’art. 29 “Diritti Sindacali” of the CCNL Rider or in your Deliveroo Rider app in the "Other" section.