I would be deeply suprirsed if the new-look Linkin Park were not one of the two missing headliners.
Saying that, I thought there was meant to be a big co-ordinated announcement of multiple European festivals today as a sign it was going to be the big announcement of their return. Evidently not.
Some on the Reading thread were talking him up as an option there. But this says he's in Australia at the time R&L is scheduled, so I take it that rules him out of that too.
Tbf most of the singles were released in 2004. So could make a case that it's a two-stage anniversary, but the album release itself was in February 2005.