Coming up today, 5 May 2020 ,Germany's constitutional court (in Karlsruhe) will announce its decision on whether the ECB's public sector purchase QE program is legal under German law.
It seems likely the decision will accept the program as legal but it could nevertheless impose restrictions on what the ECB does
- ie. it may impose conditions for the ECB's sovereign bond purchases that could impact the flexibly of policy.
Could be a EUR negative or at least prompt some volatility. A heads up.