They are. Open'er always indicates who's headlining by putting them on top of the artists list at the webpage. Maybe they'll get a co-headliner, but to call them "THE star" of the day surely makes them a headliner.
Judging by the website it seems Gracie Abrams is co-headlining Wednesday. A strong name with a different audience than Massive Attack, so it's a smart move, I think.
Anyway, great news about NIN, my gf likes Gracie a lot, so we're happy. The line-up is shaping up as very diverse, which we like the most about Open'er 🙂 And it seems we're going to come back to Poland with a group of friends this year 🙂
Oh you're right, I was there too but I was convinced that it was 17.
But still it's a president that they don't always have a clear headliner for every day, and I'm with you that Justice and Fender isn't the worst pairing, especially when you look at the other festivals this summer