I read this news from other source and there is more info then in OP link.So far Spain tax office is sent requests to 16 banks,tens of exchanges and ATMs
companies and over 40 business entities who accept cryptocurrency as a method of payment.They want all information about transactions and information about those behind these transactions.I think it's a very large operation because usually authorities hunt users on exchanges,but in this case they want to tax everything related to cryptocurrency regardless of whether the user has bought / sold crypto, withdraw money at the ATM, or bought something online with
BTC.
You can read more on this subject
here with link to official bulletin of Spain finance ministry published in March.