A bug was uncovered by physics validation checks on the first version of the frozen showers library which has been merged in !58896 (merged). @ahrynevi has promptly provided new library files which are fixing the mismodeling at large eta (> 4.5) as illustrated in the attached plot (the current version is the red points, the new one is the green points, the panel is the ratio to G4).
Since the current version in master is not good, and since we would like to start MC23 simulation very soon, I am proposing to change the default version in master without waiting for the next physics validation results. I am also marking the MR as urgent. We have discussed this strategy at the physics validation coordination meeting today.
This will change the output of Run 2, Run 3, and Run 4 simulation and will require an update of the reference files.