It's a bearer token. I mint 50 sats as a CashU token. The token is litterly just text. They can be redeemed back into Bitcoin. Here's 50 sats, try it out.

https://wallet.cashu.me/?token=cashuBo2FteBlodHRwczovL21pbnQubG53YWxsZXQuYXBwYXVjc2F0YXSBomFpSAAR30zuHMUPYXCGo2FhEGFzeEBhYmZmMjYzYTY4OTczZGUzMWI0NGI4MTgyYWExODhiM2M2MzM3NDE5NzM2MjM4N2NjNjFhZjZhMTc4MjYzY2UyYWNYIQJv-UcVv7wcw6ICbeno5ETa77s_S36a2-0FLc3nLggZ0qNhYQhhc3hAZDI0ZjNmOTk3NTE1MGExZWJmMzdkOWUyYmFiYmM2MWQwNDliZWEzNTE3Y2RjNzM1YTJlNDJjYWQ5ZjhlN2FjMGFjWCEDy7UMlA-w13LOmv1GvI9ToeZwF4VIzixGcmEMtdvr1T-jYWEIYXN4QDY4Y2QzNzc5NjdhYTI3NzFlMWIzNjc1NWUxMTAxYTM5ZWVjZDM5ZGU4YjhkZDhmOTM5ZmVhOGNjYmQ4NDRlYjNhY1ghAlk7VqrNeby04bZ4a3HxJ99-0Mqn05LJc2QomCIEToyto2FhCGFzeEA5NjBkOTkwMjliNGIxOWEwZDgzOTQzZTRhYzY5Mzg5Y2VmNDcyNDQyNTgyMzhmYjJhZGI0OGI3ZTcxODgzZmZjYWNYIQPnDD3M35AxKLprfb1zpJbg6MeLytN5vqFhKJyHkY06OqNhYQhhc3hANjY0OTAyMzNkNmJiZDA0M2I0YTZjN2U2MDE4NTYzYjQzM2Y0YjAwMjg5MTZiNzQ0ODljNzkyNGE3NmI2ZWU0NGFjWCECm38f0kZKEVl4nK7eaPeDLfXqMrCmZW1pfgnOuq_pY-ejYWECYXN4QGM5MmRjNjQ2NzMwODI3N2FkZDI4M2NhNjg2ZWU0NTVlZmE5MzhiOWY0ZDZmYTdhMDc1NTYxMDc0YzExYzcwZmJhY1ghAmtmE1G5pAmYAqdSIRsDkLHfA70jjHrJiL9ye9BHwN4h