On release of 6.2.0alpha1 the ChangeLog was automatically filled in with the history of the changes since 6.1.0.
Since during that time also the submodules were integrated into our git repositories. also the whole history of the former submodules now appear at this position of the ChangeLog.
Remove it and keep only the Core history again.
Will work out correctly on alpha2 again, when changes of all sysext will be included in the main ChangeLog.