I dont know, the information came from @roughbloke when I asked a similar question they said:
"I don’t know if it’s 3 or 6 tbh, however, I heard three and they are probably the biggest ones around.
Been some talk of post malone however I’ve heard he’s doing his own shows so make me think he’s not gunna be at reading.
wish I knew more but unfortunately I don’t. Hope it’s correct!"
eminem would be good. i think chappell/charli are pretty much confirmed. id love olivia rodrigo and/or sabrina. travis scott is very likely. patd is ok i guess not my type of music tho