It doesn’t do anything. The only reason to consider installing it is that this is cryptographically signed by another developer, so if Google tries to install safety core again, it will fail because googled signature is different. It also has a super high version number, so that Google hopefully will not think to try to install the software.

As for NATO membership in particular, all NATO members need to accept new members…

But the EU has a similar clause to help with military invasions, so the US support isn’t strictly needed for security.