These questions aren’t the right ones. It’s a browser engine still early in development. There is no startup time because there’s no product. It can’t snoop because all it does is implement web standards as they’re prescribed by the w3c.

All of those things come with a full featured browser which servo currently is not interested/funded/ready to build internally.

There was an experimental browser project called verso being worked on by a community member, but that hasn’t been updated in some time.