devtrackers.gg
I can confirm it's a permanent free 30-tier pass that won't go away. Progress and unlock content at your leisure (largely driven by the new match xp beta system)
Do we know whats on the pass?
It's largely focused on Reach related content that didn't make it out the door yet (and will include the S1 Mk V core for free). We'll have a livestream prior to 11/8 where the team will do some show-and-tell with the build.