https://eur-lex.europa.eu/eli/dir/2009/50/oj
The EU has agreed upon programs in order to bring in, through an immigration policy, high skilled persons from non-member states. More importantly, working within the member nations, as to which member nation would want MITRE to be located within their borders, is not something that is a hard sell given that it has economic advantages for whichever state(s) onboard MITRE.