Digital infrastructure and the uneven integration of regulatory authority: the European digital identity wallet

European digital regulation increasingly embeds legal conditions in common technical infrastructures, but common specification need not fix the immediate response to non-compliance. This article develops functional coupling as a way to analyse where adjacent regulatory functions become linked within a machine-mediated rule application. It examines the European Digital Identity Wallet through a bounded census of 15 safeguards and a structured comparison of seven transaction-time controls. Six of the seven transaction predicates are fully machine-decidable, yet only two controls impose a fixed root-level disposition; four retain bounded provider or user choice. A source-specific reanalysis shows that generic ability to stop transactions cannot be treated as equivalent to predicate-specific blocking capacity. The findings therefore concern architecturally specified regulatory visibility and immediate transaction disposition, not observed deployment or responsibility in a broader legal sense. The case shows how common EU digital infrastructure can integrate specification and visibility more tightly than immediate transaction closure while leaving execution and later responsibility distributed across providers, users and public authorities.