The Joint Declaration was agreed upon at an informal meeting of the European Chiefs of Police in London hosted by the National Crime Agency on 18 April.
Police Chiefs of all EU Member States and Schengen Associated Countries were invited, alongside Europol’s Executive Director.
Here is the declaration (pdf).
Hungary is in bed with the CCP. Maybe the other police forces see advantages to themselves. It remains to be seen which of these chiefs are still in their positions a year from now, given the EU’s generally pro-privacy stance