We didn't change anything in regards to installation. That was PHP 7 compatibility fix in the archive class. It's a generic class used for handling archives. Ideally we need to just get rid of it, but that's for a future release.
We didn't do an install test after those changes as we each assumed someone else on the team did and the fixes were done outside of an IDE (in a replace script) so the error didn't catch. Chain of unfortunate events resulted in what you experience. Things happen, we're human, and we make mistakes sometimes, sorry.
A new nightly has been pushed with the issue fixed and properly install tested.