According to the announcement: "Trademarks will not be automatically reserved. But there will be an objection-based mechanism for trademark owners where their arguments for protection will be considered."
How expensive or practical is it to trademark .onion for purposes of the Tor network? "There will be a limited application period where any established entity from anywhere in the world can submit an application that will go through an evaluation process." Is an application to ICANN being considered? The Tor project and network is a well established entity, having an office etc and thousands of relay nodes (by next year).