It is surely an encrypted stack trace, encoded in base64, which is probably being spit out by the load balancer proxy. I would not be surprised if Youtube devel

It is surely an encrypted stack trace, encoded in base64, which is probably being spit out by the load balancer proxy. I would not be surprised if Youtube developers used their own Chrome extension for making that binary meat readable. I have once set out to write a module for Nodejs for the same purpose, but never finished it. Can't really see a downside in this way of reporting errors.